Shape memory polymers

ABSTRACT

The present disclosure relates to Shape Memory Polymers (SMP&#39;s) comprising function groups that allow the polymers to be elastically deformed, utilized in the elastically deformed state, and subsequently returned to the original polymorphic shape.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority to the U.S. Provisional Application No.60/854,249, filed Oct. 25, 2006, the disclosure of which application ishereby incorporated in its entirety by this reference.

FIELD OF THE DISCLOSURE

The present disclosure relates to Shape Memory Polymers (SMP's) thathave surprising properties wherein the polymers can be elasticallydeformed, utilized in the elastically deformed state, and subsequentlyreturned to the original polymorphic shape.

BACKGROUND OF THE DISCLOSURE

Most materials behave elastically at low levels of strain. Forcrystalline solids and amorphous glasses, elasticity occurs up to astrain limit rarely exceeding 1%. Elastic strain is related to theextent to that atoms are dislodged from their equilibrium positions.However, elasticity in polymers is very different, and polymericmaterials can exhibit elastic behavior to several hundred percentstrain. Polymeric elastomers are usually high molecular weightmolecules, well above their glass transition temperature T_(G), and theytypically contain a network of chemical or physical crosslinks that actas permanent entanglements and restrict long range (irreversible)slippage of chains. When a polymer elastomer is stretched, a restoringforce arises because molecular chains are distorted from their mostprobable and preferable configuration—this phenomenon is known asentropic elasticity. Several classes of polymers exhibit entropicelasticity, including natural and synthetic rubbers and polyurethanes.

Entropy-based elasticity must be differentiated from the so called“shape-memory effect” defined by the literature. A shape-memory materialis one that returns to its original shape only after the application ofan external stimulus (Irie, “Shape Memory Materials.” Chapter 9: “ShapeMemory Polymers” Otsuka and Wayman eds. Campbridge University Press,1998). For example, a thermo-responsive shape-memory material returns toits “remembered” shape only upon heating past a critical shape-memorytemperature T_(SM). Above T_(SM) such a material can be elasticallydeformed by subjecting it to external stresses, and then cooling it(while under stress) beneath T_(SM). In the cooled state, externalstresses can be removed and the material retains its deformed shape.Upon subsequent heating above T_(SM), the material recovers its elasticstrain energy and returns to its original shape. Metallic alloys andceramics are well-known to exhibit this shape-memory effect.Shape-memory polymers (SMP's) are noted for their ability to recoverextremely large strains—up to several hundred percent—that are imposedby mechanical loading. The large-strain recovery observed in SMP's is amanifestation of entropy elasticity.

SMP's offer tremendous advantages to the fields of biotechnology andmedicine (Lindlein et al., “Shape Memory Polymers” Angew. Chem. Int. Ed.41, p 2034 (2002)). By exploiting the large-strain recovery of SMP's,surgeons can implant bulky objects into the body through smallincisions. Biodegradable SMP's enable the development of degradablesutures and vascular stents. Biological MicroElectroMechanic Systems(Bio-MEMS) can perform intricate gripping, releasing, or even stitchingoperations. SMP's can also be used in non-biological applicationsincluding rewritable storage media, intelligent packaging materials,shapeable tools, and deployable objects for space exploration. SMP's canalso be used in the development of recyclable thermosets and materialsprocessing.

Solid state elastomers that utilize thermoreversible self-association offunctional groups offer a novel way to stabilize mechanically deformedstates, and the potential of such materials as shape-memory materialshas not previously been studied. Therefore, there is a long felt need inthe art for shape memory polymers containing self-associating chemicalcrosslinkers.

SUMMARY OF THE DISCLOSURE

The present disclosure meets the aforementioned needs in that it hasbeen surprisingly discovered that incorporation of certain functionalgroups into polymer backbones affords these polymers the ability toconserve, or mechanically stabilize elastically deformed states ofstrain in polymeric materials.

The present disclosure relates to shape memory polymers having theformula:

—[HB]_(x)-[MOD]_(y)-[XL]_(z)-

comprising:

-   i) hydrogen bonding units, HB, having at least one hydrogen bond    donor moiety and at least one hydrogen bond acceptor moiety;-   ii) backbone modifier units, MOD; and-   iii) crosslinking units, XL, that are capable of forming one or more    irreversible crosslinks;    the index x is from about 0.5 to about 20, the index y is from about    75 to about 99.6, and the index z is from about 0.1 to about 5;    wherein the polymer is characterized by having a shape memory    temperature, T_(SM), such that the polymer can be elastically    deformed at the shape memory temperature, and subsequently lowered    to a shape memory freezing temperature, T_(F), and the method of    elastic deformation is removed, the polymer will return to its,    original shape with a rate slower than the rate observed if the    method of mechanical elastic deformation were removed at T_(SM);    provided the shape memory freezing temperature T_(F) is above the    glass transition, T_(G), of the polymer, and provided the polymer is    in the amorphous state at T_(F).

These and other objects, features and advantages will become apparent tothose of ordinary skill in the art from a reading of the followingdetailed description and the appended claims. All percentages, ratiosand proportions herein are by weight, unless otherwise specified. Alltemperatures are in degrees Celsius (° C.) unless otherwise specified.All documents cited are in relevant part, incorporated herein byreference.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1. is a schematic of how the Shape Memory Polymers disclosed hereinre-associate after being elastically strained.

FIG. 2. is a graph of the isothermal (47° C.) creep data for the polymerof Example 4 using a 50 mN tensile load (solid line) and theleast-squares fit of these data to the non-linear constitutive model(dotted line).

FIG. 3. is a diagram showing the mechanical elements of the constitutivemodel: spring element (E₁) and Maxwell element (E₂, η(T)) in series.

FIG. 4. depicts the Arrhenius temperature-dependence of fittedviscosities obtained from creep data for the polymers of Examples 4 and5 measured at various temperatures.

FIG. 5. depicts the shape-memory response curve of the polymer ofExample 4.

FIG. 6. depicts the percent strain of the polymer of Example 4 atvarious temperatures over time.

DETAILED DESCRIPTION OF THE DISCLOSURE

Throughout this specification, unless the context requires otherwise,the word “comprise,” or variations such as “comprises” or “comprising,”will be understood to imply the inclusion of a stated integer or step orgroup of integers or steps but not the exclusion of any other integer orstep or group of integers or steps.

It must be noted that, as used in the specification and the appendedclaims, the singular forms “a,” “an” and “the” include plural referentsunless the context clearly dictates otherwise.

“Optional” or “optionally” means that the subsequently described eventor circumstance can or cannot occur, and that the description includesinstances where the event or circumstance occurs and instances where itdoes not.

Ranges can be expressed herein as from “about” one particular value,and/or to “about” another particular value. When such a range isexpressed, another aspect includes from the one particular value and/orto the other particular value. Similarly, when values are expressed asapproximations, by use of the antecedent “about,” it will be understoodthat the particular value forms another aspect. It will be furtherunderstood that the endpoints of each of the ranges are significant bothin relation to the other endpoint, and independently of the otherendpoint. It is also understood that there are a number of valuesdisclosed herein, and that each value is also herein disclosed as“about” that particular value in addition to the value itself. Forexample, if the value “10” is disclosed, then “about 10” is alsodisclosed. It is also understood that when a value is disclosed that“less than or equal to” the value, “greater than or equal to the value,”and possible ranges between values are also disclosed, as appropriatelyunderstood by the skilled artisan. For example, if the value “10” isdisclosed, then “less than or equal to 10” as well as “greater than orequal to 10” is also disclosed. It is also understood that throughoutthe application data are provided in a number of different formats andthat these data represent endpoints and starting points and ranges forany combination of the data points. For example, if a particular datapoint “10” and a particular data point “15” are disclosed, it isunderstood that greater than, greater than or equal to, less than, lessthan or equal to, and equal to 10 and 15 are considered disclosed aswell as between 10 and 15. It is also understood that each unit betweentwo particular units are also disclosed. For example, if 10 and 15 aredisclosed, then 11, 12, 13, and 14 are also disclosed.

A weight percent of a component, unless specifically stated to thecontrary, is based on the total weight of the formulation or compositionin which the component is included.

By “sufficient amount” and “sufficient time” means an amount and timeneeded to achieve the desired result or results, e.g., dissolve aportion of the polymer.

“Admixture” or “blend” is generally used herein means a physicalcombination of two or more different components. In the case ofpolymers, an admixture, or blend, of polymers is a physical blend orcombination of two or more different polymers as opposed to a copolymerthat is single polymeric material that is comprised of two or moredifferent monomers.

“Molecular weight” as used herein, unless otherwise specified, refersgenerally to the relative average chain length of the bulk polymer. Inpractice, molecular weight can be estimated or characterized in variousways including gel permeation chromatography (GPC) or capillaryviscometry. GPC molecular weights are reported as the weight-averagemolecular weight (M_(w)) as opposed to the number-average molecularweight (M_(n)). Capillary viscometry provides estimates of molecularweight as the Inherent Viscosity determined from a dilute polymersolution using a particular set of concentration, temperature, andsolvent conditions.

The term “number average molecular weight” (M_(n)) is defined herein asthe mass of all polymer molecules divided by the number of moleculesthat are present.

The term “weight average molecular weight” (M_(w)) is defined herein asthe mass of a sample of a shape memory polymer divided by the totalnumber of molecules that are present.

The present disclosure relates to Shape Memory Polymers (SMP's) havingsurprising properties. The Shape Memory Polymers of the presentdisclosure have three distinct features and/or advantages:

-   -   i) the SMP's are transparent to light at all processing        temperatures; they have no glassy or crystalline domains that        can scatter light;

ii) the SMP's exhibit amorphous or rubbery “fixed” states; therebyproviding a malleable polymer that functionality can be taken advantageof for permanent as well as temporary uses; and

-   -   iii) the SMP's can be precisely tuned to have differential        recovery rates and recovery temperatures based upon the specific        need of the formulator.

The Shape memory Polymers of the present disclosure consist of acrosslinked polymer containing reversibly associating side-groups. Aschematic of the polymer architecture is shown in FIG. 1. When thematerial is elastically strained, self-complementary side-groupsassociate to temporarily hold or “pin” the material in its strainedstate. Since the association of side-groups is a completely reversibleprocess, the material slowly relaxes to its original, equilibrium shape.From an architectural standpoint, the material can be viewed as havingcovalent crosslinks that are superimposed onto dynamic, non-covalentcrosslinks. The material stiffness is determined by the number ofcovalent crosslinks, and its shape recovery rate is determined by thenumber of non-covalent crosslinks and the dynamics of associatingside-groups.

The polymers of the present disclosure have a unique combination ofproperties due to their constituent units that allow the polymers to bedeformed or elastically strained from a first shape or size, thensubsequently become temporarily pinned into a second deformed orelastically strained state. The hydrogen bonds formed by the HydrogenBonding Units described herein below, serve to lock or pin the polymersinto the second state. The polymers of the present disclosure can bereturned to the initial state by one of three ways described hereinbelow.

Typically the shape memory polymers are elastically deformed or strainedat a particular temperature, the shape memory temperature, T_(SM), thatis particular for each application for which the polymer is used and isunique to each polymeric species. First the polymer is raised to atemperature, T_(SM), that provides necessary energy for fastdissociation of existing hydrogen bonds between various units andthereby enables the deformation of the polymer into the desired secondshape or configuration. Then the polymer is elastically strained by anapplied mechanical force and subsequently cooled to a temperature thatis referred to herein as the shape memory freezing temperature, T_(F),that is also unique to each species of polymer and can be manipulated bythe formulator, usually by selection of the type and number of hydrogenbonding units in the polymer. After cooling to the shape memory freezingtemperature, the mechanical load is removed. During cooling and beforethe mechanical elastically straining force is removed, the hydrogenbonding units begin to form new local hydrogen bonds with other unitsalso capable of forming hydrogen bonds. These newly formed hydrogenbonds now serve to lock or pin the polymer into the deformed or strainedconfiguration.

A single hydrogen bond is relatively weak, typically on the order of 5to 40 kJ/mol. By increasing or decreasing the number of hydrogen bondingunits, and, therefore, the number of possible hydrogen bonds capable ofbeing formed within a molecule, the formulator can adjust both the shapememory temperature, as well as the shape memory freezing temperature.However, since one of the advantages of the present polymers is theirlight transparency and amorphous state, the shape freezing temperature,T_(F), can be well above the glass transition temperature, T_(G).

The polymers of the present disclosure also exhibit characteristicstrain recovery and mechanical creep that are properties of theparticular species and can be adjusted by the formulator. If, forexample a mechanical load is applied, cumulative hydrogen bond forcesstabilize the polymer's mechanical state, resisting creep. Themechanical creep rate depends on temperature and is much faster athigher temperatures. Furthermore, if a mechanical load is removed,cumulative hydrogen bonds stabilize the polymer's strained state,resisting shape recovery. Likewise, the rate of shape recovery dependson temperature and is much faster at higher temperature. However, theshape memory polymers disclosed herein can be elastically strained byany method that distends the polymer, for example thermally,electrically, and the like.

Mechanical creep behavior and shape recovery can be studied using athermogravimetric analysis apparatus. FIG. 2 represents the isothermalmechanical creep data acquired on the polymer described in Example 4herein below. The measurement temperature was 47° C. and the mechanicalload was 50 mN. The dotted line represents the line derived from themathematical model derived from the constitutive equation below, whereasthe solid line represents a least-square fit to the data using a simplemodel such as that shown in FIG. 3. In FIG. 1, E₁ and E₂ refer to theelastic moduli corresponding to the springs in the model and η(T) refersto the temperature dependent viscosity that is typically measuredisothermally in order to design into the polymer the desired recoveryrate at the temperature at which the polymer will be used. E₁ describesthe polymer's instantaneous response to a stress and E₂ and η(T) takenin series with one another represent a Maxwell element. The constitutiveequation for this model is:

$\begin{matrix}{{{\left( {E_{1} + E_{2}} \right)\sigma} + {{\eta (T)}\frac{\sigma}{t}}} = {{E_{1}E_{2}\gamma} + {E_{1}{\eta (T)}\frac{\gamma}{t}}}} & {{Equation}\mspace{14mu} 1}\end{matrix}$

where σ is applied stress and γ is polymer elongation. For a creepexperiment, the initial condition is γ=0 and the boundary condition isspecified by the applied load, i.e. σ is constant.

Non-linear least square regression fits to Equation 1 using isothermalcreep data, such as those shown in FIG. 2, result in values for E₁, E₂,and η. A plot of ln(η) against inverse temperature is shown in FIG. 4for two of the samples discussed herein. By utilizing data such as thosefound in FIG. 4, the formulator can determine the relative rate ofelongation change, dγ/dt, and therefore the relaxation rate or creep fora particular polymer.

FIG. 5 depicts an example of the shape-memory response curve for thepolymer of Example 4. Shape-memory response curves such as this can beutilized by the formulator to determine the effects that adjustments inthe polymer composition will have on relaxation times and other featuresof the polymer's shape memory response. For example, the solid line inFIG. 4 indicates the percent strain of the polymer at a particulartemperature. As the data indicate, the polymer of Example 4 was firstequilibrated at the T_(SM) (66° C.) for 20 minutes after which amechanical force of 50 mN was applied. This force resulted in rapidelongation (solid line) of the shape memory polymer. While maintainingthe 50 mN applied force, the temperature of the shape memory polymer wasthen lowered to the T_(F) (5° C.). Cooling the polymer furthers itselongation to its maximum (ε_(m), solid line) that is due to entropyelasticity, and will vary in amount from species to species. Once thepolymer is equilibrated at the T_(F) temperature, the mechanical forceis removed and the polymer begins to creep back to its original state ata relaxation rate depicted by the section of the curve immediatelyfollowing ε_(u). This rate of deformation is slow but can be acceleratedby increasing temperature. As can be seen in FIG. 4, there is a sharpinflection in the curve at the point wherein the temperature of thepolymer is raised above the T_(F). The formulator, by extrapolatingoutward the curve of percent strain (level of relaxation) versus timemeasured isothermally at T_(F), will be able to determine how long itwill take the shape-memory polymer to return to the original state. Thisinformation will allow the formulator to determine the effects onpolymer relaxation rates that adjustments in the relative amounts ofpolymer constituents will have.

The polymers of the present disclosure are comprised of three types ofunits:

i) Hydrogen Bonding Units—HB;

ii) Backbone Modifying Units—MOD; and

iii) Crosslinking Units—XL.

Each of these units fulfills a function that affects the properties ofthe final polymer. The Hydrogen Bonding Units serve to form temporarycrosslinks between polymer chains (inter chain hydrogen bonding) orsemi-permanent crosslinks between other hydrogen bonding units of thesame polymer chain (intra chain hydrogen bonding). These HB units serveto temporarily “pin” the polymers of the present disclosure into anelastically strained state. While HB units do undergo dissociation belowT_(F), at low temperatures (below T_(F)) the dissociation rate is slowenough that the polymer remains elongated for relevant applicationtimescales.

The formulator, by incorporating more or less hydrogen bonding unitsinto the shape memory polymer will be able to control the relaxationrate or creep recovery of the polymer back as it returns to its originalform (permanent shape) at a given temperature. For a given temperature,increasing the number of hydrogen bonding units will cause a slowerrelaxation rate, while decreasing the number of hydrogen bonding unitswill cause the polymer to have a faster relaxation rate. In addition,the number of crosslinking units and their length will also affect therelaxation rate.

One way in which the formulator can cause the polymers to rapidly relaxinto the original state is to raise the temperature of the materialabove the shape memory temperature, T_(SM), or to a temperature aboveit. Raising the temperature of the polymer above T_(F) will alsoincrease the rate of creep, but at a slower rate than raising thetemperature to T_(SM) or above.

The present disclosure utilizes the term “hydrogen bond” in the samemanner as the artisan of ordinary skill. The terms “hydrogen bondacceptor moiety” and “hydrogen bond donor moiety” are defined herein as“moieties that are capable when at least one acceptor moiety is presentand at least one donor moiety is present, of forming a hydrogen bond.”

The following are non-limiting examples of the hydrogen bonding formedby the units that comprise the shape memory polymers of the presentdisclosure:

i) an example of two similar units that are capable of forming twohydrogen bonds between the units.

ii) an example of two different units that are capable of forming threehydrogen bonds between the units.

iii) an example of a hydrogen bonding unit wherein hydrogen bonds areformed between Z units (donors) and R⁴ units (acceptors) that arefurther described herein below. Those of ordinary skill in the art willalso recognize the presence of a potential intra moiety hydrogen bond(arrow) that can help further determine the orientation of the Z and R⁴units relative to one another by further assisting in holding thehydrogen bonding units in alignment.

It will be understood by the artisan of ordinary skill, that otherrefinements and changes to the Q units defined herein below viamodification of R⁴, W, Y, and Z, that are also further defined hereinbelow, will provide variation in the degree of hydrogen bonding. Asshown below, substitution of the ring N—H units will be another meansfor the formulator to adjust the alignment of hydrogen bonding units inthe Q units of the present disclosure, for example, the units having theformula:

As will be seen further herein below in the description of the presentdisclosure, the formulator will have great latitude in choosing unitsthat will provide more or less hydrogen bonding, and therefore providethe formulator with a method for varying the properties of the shapememory polymers. The propitious choice of R⁴ units, mixtures, orvariations in R⁴ will allow the formulator profound latitude in creatingvarious arrays of hydrogen bonds.

The following chemical hierarchy is used throughout the specification todescribe and enable the scope of the present disclosure and toparticularly point out and distinctly claim the units that comprise thecompounds of the present disclosure, however, unless otherwisespecifically defined, the terms used herein are the same as those of theartisan of ordinary skill. The term “hydrocarbyl” stands for any carbonatom-based unit (organic molecule), the units optionally containing oneor more organic functional group, including inorganic atom comprisingsalts, inter alia, carboxylate salts, quaternary ammonium salts. Withinthe broad meaning of the term “hydrocarbyl” are the classes “acyclichydrocarbyl” and “cyclic hydrocarbyl” and are used to divide hydrocarbylunits into cyclic and non-cyclic classes.

As it relates to the following definitions, “cyclic hydrocarbyl” unitsmay comprise only carbon atoms in the ring (carbocyclic and aryl rings)or may comprise one or more heteroatoms in the ring (heterocyclic andheteroaryl). For “carbocyclic” rings the lowest number of carbon atomsin a ring are 3 carbon atoms; cyclopropyl. For “aryl” rings the lowestnumber of carbon atoms in a ring are 6 carbon atoms; phenyl. For“heterocyclic” rings the lowest number of carbon atoms in a ring is 1carbon atom; diazirinyl. Ethylene oxide comprises 2 carbon atoms and isa C₂ heterocycle. For “heteroaryl” rings the lowest number of carbonatoms in a ring is 1 carbon atom; 1,2,3,4-tetrazolyl. The following is anon-limiting description of the terms “acyclic hydrocarbyl” and “cyclichydrocarbyl” as used herein.

A. Substituted and Unsubstituted Acyclic Hydrocarbyl:

For the purposes of the present disclosure the term “substituted andunsubstituted acyclic hydrocarbyl” encompasses 3 categories of units:

-   1) linear or branched alkyl, non-limiting examples of that include,    methyl (C₁), ethyl (C₂), n-propyl (C₃), iso-propyl (C₃), n-butyl    (C₄), sec-butyl (C₄), iso-butyl (C₄), tert-butyl (C₄), and the like;    substituted linear or branched alkyl, non-limiting examples of which    includes, hydroxymethyl (C₁), chloromethyl (C₁), trifluoromethyl    (C₁), aminomethyl (C₁), 1-chloroethyl (C₂), 2-hydroxyethyl (C₂),    1,2-difluoroethyl (C₂), 3-carboxypropyl (C₃), and the like.-   2) linear or branched alkenyl, non-limiting examples of which    include, ethenyl (C₂), 3-propenyl (C₃), 1-propenyl (also    2-methylethenyl) (C₃), isopropenyl (also 2-methylethen-2-yl) (C₃),    buten-4-yl (C₄), and the like; substituted linear or branched    alkenyl, non-limiting examples of which include, 2-chloroethenyl    (also 2-chlorovinyl) (C₂), 4-hydroxybuten-1-yl (C₄),    7-hydroxy-7-methyloct-4-en-2-yl (C₉),    7-hydroxy-7-methyloct-3,5-dien-2-yl (C₉), and the like.-   3) linear or branched alkynyl, non-limiting examples of which    include, ethynyl (C₂), prop-2-ynyl (also propargyl) (C₃),    propyn-1-yl (C₃), and 2-methyl-hex-4-yn-1-yl (C₇); substituted    linear or branched alkynyl, non-limiting examples of which include,    5-hydroxy-5-methylhex-3-ynyl (C₇), 6-hydroxy-6-methylhept-3-yn-2-yl    (C₉), 5-hydroxy-5-ethylhept-3-ynyl (C₉), and the like.

B. Substituted and Unsubstituted Cyclic Hydrocarbyl:

For the purposes of the present disclosure the term “substituted andunsubstituted cyclic hydrocarbyl” encompasses 5 categories of units:

-   1) The term “carbocyclic” is defined herein as “encompassing rings    comprising from 3 to 20 carbon atoms, wherein the atoms that    comprise the rings are limited to carbon atoms, and further each    ring can be independently substituted with one or more moieties    capable of replacing one or more hydrogen atoms.” The following are    non-limiting examples of “substituted and unsubstituted carbocyclic    rings” that encompass the following categories of units:    -   i) carbocyclic rings having a single substituted or        unsubstituted hydrocarbon ring, non-limiting examples of which        include, cyclopropyl (C₃), 2-methyl-cyclopropyl (C₃),        cyclopropenyl (C₃), cyclobutyl (C₄), 2,3-dihydroxycyclobutyl        (C₄), cyclobutenyl (C₄), cyclopentyl (C₅), cyclopentenyl (C₅),        cyclopentadienyl (C₅), cyclohexyl (C₆), cyclohexenyl (C₆),        cycloheptyl (C₇), cyclooctanyl (C₈), decalinyl (C₁₀),        2,5-dimethylcyclopentyl (C₅), 3,5-dichlorocyclohexyl (C₆),        4-hydroxycyclohexyl (C₆), and 3,3,5-trimethylcyclohex-1-yl (C₆).    -   ii) carbocyclic rings having two or more substituted or        unsubstituted fused hydrocarbon rings, non-limiting examples of        which include, octahydropentalenyl (C₈), octahydro-1H-indenyl        (C₉), 3a,4,5,6,7,7a-hexahydro-3H-inden-4-yl (C₉),        decahydroazulenyl (C₁₀).    -   iii) carbocyclic rings that are substituted or unsubstituted        bicyclic hydrocarbon rings, non-limiting examples of which        include, bicyclo-[2.1.1]hexanyl, bicyclo[2.2.1]heptanyl,        bicyclo[3.1.1]heptanyl, 1,3-dimethyl[2.2.1]heptan-2-yl,        bicyclo[2.2.2]octanyl, and bicyclo[3.3.3]undecanyl.-   2) The term “aryl” is defined herein as “units encompassing at least    one phenyl or naphthyl ring and wherein there are no heteroaryl or    heterocyclic rings fused to the phenyl or naphthyl ring and further    each ring can be independently substituted with one or more moieties    capable of replacing one or more hydrogen atoms.” The following are    non-limiting examples of “substituted and unsubstituted aryl rings”    that encompass the following categories of units:    -   i) C₆ or C₁₀ substituted or unsubstituted aryl rings; phenyl and        naphthyl rings whether substituted or unsubstituted,        non-limiting examples of which include, phenyl (C₆),        naphthylen-1-yl (C₁₀), naphthylen-2-yl (C₁₀), 4-fluorophenyl        (C₆), 2-hydroxyphenyl (C₆), 3-methylphenyl (C₆),        2-amino-4-fluorophenyl (C₆), 2-(N,N-diethylamino)phenyl (C₆),        2-cyanophenyl (C₆), 2,6-di-tert-butylphenyl (C₆),        3-methoxyphenyl (C₆), 8-hydroxynaphthylen-2-yl (C₁₀),        4,5-dimethoxynaphthylen-1-yl (C₁₀), and 6-cyano-naphthylen-1-yl        (C₁₀).    -   ii) C₆ or C₁₀ aryl rings fused with 1 or 2 saturated rings        non-limiting examples of which include,        bicyclo[4.2.0]octa-1,3,5-trienyl (C₈), and indanyl (C₉).-   3) The terms “heterocyclic” and/or “heterocycle” are defined herein    as “units comprising one or more rings having from 3 to 20 atoms    wherein at least one atom in at least one ring is a heteroatom    chosen from nitrogen (N), oxygen (O), or sulfur (S), or mixtures of    N, O, and S, and wherein further the ring that comprises the    heteroatom is also not an aromatic ring.” The following are    non-limiting examples of “substituted and unsubstituted heterocyclic    rings” that encompass the following categories of units:    -   i) heterocyclic units having a single ring containing one or        more heteroatoms, non-limiting examples of which include,        diazirinyl (C₁), aziridinyl (C₂), urazolyl (C₂), azetidinyl        (C₃), pyrazolidinyl (C₃), imidazolidinyl (C₃), oxazolidinyl        (C₃), isoxazolinyl (C₃), isoxazolyl (C₃), thiazolidinyl (C₃),        isothiazolyl (C₃), isothiazolinyl (C₃), oxathiazolidinonyl (C₃),        oxazolidinonyl (C₃), hydantoinyl (C₃), tetrahydrofuranyl (C₄),        pyrrolidinyl (C₄), morpholinyl (C₄), piperazinyl (C₄),        piperidinyl (C₄), dihydropyranyl (C₅), tetrahydropyranyl (C₅),        piperidin-2-onyl (valerolactam) (C₅),        2,3,4,5-tetrahydro-1H-azepinyl (C₆), 2,3-dihydro-1H-indole (C₉),        and 1,2,3,4-tetrahydro-quinoline (C₉).    -   ii) heterocyclic units having 2 or more rings one of which is a        heterocyclic ring, non-limiting examples of which include        hexahydro-1H-pyrrolizinyl (C₇),        3a,4,5,6,7,7a-hexahydro-1H-benzo[d]imidazolyl (C₇),        3a,4,5,6,7,7a-hexahydro-1H-indolyl (C₈),        1,2,3,4-tetrahydroquinolinyl (C₉), and        decahydro-1H-cycloocta[b]pyrrolyl (C₁₀).-   4) The term “heteroaryl” is defined herein as “encompassing one or    more rings comprising from 5 to 20 atoms wherein at least one atom    in at least one ring is a heteroatom chosen from nitrogen (N),    oxygen (O), or sulfur (S), or mixtures of N, O, and S, and wherein    further at least one of the rings that comprises a heteroatom is an    aromatic ring.” The following are non-limiting examples of    “substituted and unsubstituted heterocyclic rings” that encompass    the following categories of units:    -   i) heteroaryl rings containing a single ring, non-limiting        examples of which include, 1,2,3,4-tetrazolyl (C₁),        [1,2,3]triazolyl (C₂), [1,2,4]triazolyl (C₂), triazinyl (C₃),        thiazolyl (C₃), 1H-imidazolyl (C₃), oxazolyl (C₃), furanyl (C₄),        thiopheneyl (C₄), pyrimidinyl (C₄), 2-phenylpyrimidinyl (C₄),        pyridinyl (C₅), 3-methylpyridinyl (C₅), and        4-dimethylaminopyridinyl (C₅)    -   ii) heteroaryl rings containing 2 or more fused rings one of        which is a heteroaryl ring, non-limiting examples of which        include: 7H-purinyl (C₅), 9H-purinyl (C₅), 6-amino-9H-purinyl        (C₅), 5H-pyrrolo[3,2-d]pyrimidinyl (C₆),        7H-pyrrolo[2,3-d]pyrimidinyl (C₆), pyrido[2,3-d]pyrimidinyl        (C₇), 2-phenylbenzo[d]thiazolyl (C₇), 1H-indolyl (C₈),        4,5,6,7-tetrahydro-1-H-indolyl (C₉), quinoxalinyl (C₉),        5-methylquinoxalinyl (C₈), quinazolinyl (C₈), quinolinyl (C₉),        8-hydroxy-quinolinyl (C₉), and isoquinolinyl (C₉).-   5) C₁-C₆ tethered cyclic hydrocarbyl units (whether carbocyclic    units, C₆ or C₁₀ aryl units, heterocyclic units, or heteroaryl    units) that are connected to another moiety, unit, or core of the    molecule by way of a C₁-C₆ alkylene unit. Non-limiting examples of    tethered cyclic hydrocarbyl units include benzyl C₁-(C₆) having the    formula:

-    wherein R^(a) is optionally one or more independently chosen    substitutions for hydrogen. Further examples include other aryl    units, inter alia, (2-hydroxyphenyl)Hexyl C₆-(C₆);    naphthalen-2-ylmethyl C₁-(C₁₀), 4-fluorobenzyl C₁-(C₆),    2-(3-hydroxy-phenyl)ethyl C₂-(C₆), as well as substituted and    unsubstituted C₃-C₁₀ alkylenecarbocyclic units, for example,    cyclopropylmethyl C₁-(C₃), cyclopentylethyl C₂-(C₅),    cyclohexylmethyl C₁-(C₆). Included within this category are    substituted and unsubstituted C₁-C₁₀ alkylene-heteroaryl units, for    example a 2-picolyl C₁-(C₆) unit having the formula:

-    wherein R^(a) is the same as defined above. In addition, C₁-C₁₂    tethered cyclic hydrocarbyl units include C₁-C₁₀    alkyleneheterocyclic units and alkylene-heteroaryl units,    non-limiting examples of which include, aziridinylmethyl C₁-(C₂) and    oxazol-2-ylmethyl C₁-(C₃).

For the purposes of the present disclosure carbocyclic rings are from C₃to C₂₀; aryl rings are C₆ or C₁₀; heterocyclic rings are from C₁ to C₉;and heteroaryl rings are from C₁ to C₉.

For the purposes of the present disclosure, and to provide consistencyin defining the present disclosure, fused ring units, as well asspirocyclic rings, bicyclic rings and the like, that comprise a singleheteroatom will be characterized and referred to herein as beingencompassed by the cyclic family corresponding to the heteroatomcontaining ring, although the artisan may have alternativecharacterizations. For example, 1,2,3,4-tetrahydroquinoline having theformula:

is, for the purposes of the present disclosure, considered aheterocyclic unit. 6,7-Dihydro-5H-cyclopentapyrimidine having theformula:

is, for the purposes of the present disclosure, considered a heteroarylunit. When a fused ring unit contains heteroatoms in both a saturatedring (heterocyclic ring) and an aryl ring (heteroaryl ring), the arylring will predominate and determine the type of category to which thering is assigned herein for the purposes of describing the disclosure.For example, 1,2,3,4-tetrahydro-[1,8]naphthyridine having the formula:

is, for the purposes of the present disclosure, considered a heteroarylunit.

The term “substituted” is used throughout the specification. The term“substituted” is applied to the units described herein as “substitutedunit or moiety is a hydrocarbyl unit or moiety, whether acyclic orcyclic, that has, one or more hydrogen atoms replaced by a substituentor several substituents as defined herein below.” The units, whensubstituting for hydrogen atoms are capable of replacing one hydrogenatom, two hydrogen atoms, or three hydrogen atoms of a hydrocarbylmoiety at a time. In addition, these substituents can replace twohydrogen atoms on two adjacent carbons to form the substituent, newmoiety, or unit. For example, a substituted unit that requires a singlehydrogen atom replacement includes halogen, hydroxyl, and the like. Atwo hydrogen atom replacement includes carbonyl, oximino, and the like.A two hydrogen atom replacement from adjacent carbon atoms includesepoxy, and the like. Three hydrogen replacement includes cyano, and thelike. The term substituted is used throughout the present specificationto indicate that a hydrocarbyl moiety, inter alia, aromatic ring, alkylchain; can have one or more of the hydrogen atoms replaced by asubstituent. When a moiety is described as “substituted” any number ofthe hydrogen atoms may be replaced. For example, 4-hydroxyphenyl is a“substituted aromatic carbocyclic ring (aryl ring)”,(N,N-dimethyl-5-amino)octanyl is a substituted C₈ linear alkyl unit,3-guanidinopropyl is a “substituted C₃ linear alkyl unit,” and2-carboxypyridinyl is a “substituted heteroaryl unit.”

The following are non-limiting examples of units that can substitute forhydrogen atoms on a carbocyclic, aryl, heterocyclic, or heteroaryl unit:

-   -   i) C₁-C₄ linear or branched alkyl; for example, methyl (C₁),        ethyl (C₂), n-propyl (C₃), iso-propyl (C₃), n-butyl (C₄),        iso-butyl (C₄), sec-butyl (C₄), and tert-butyl (C₄);    -   ii) —OR³⁰; for example, —OH, —OCH₃, —OCH₂CH₃, —OCH₂CH₂CH₃;    -   iii) —C(O)R³⁰; for example, —(OCH₃, —COCH₂CH₃, COCH₂CH₂CH₃;    -   iv) —C(O)OR³⁰; for example, —CO₂CH₃, —CO₂CH₂CH₃, —CO₂CH₂CH₂CH₃;    -   v) —C(O)N(R³⁰)₂; for example, —CONH₂, —CONHCH₃, —CON(CH₃)₂;    -   vi) —N(R³⁰)₂; for example, —NH₂, —NHCH₃, —N(CH₃)₂, —NH(CH₂CH₃);    -   vii) halogen: —F, —Cl, —Br, and —I;    -   viii) —CH_(m)X_(n); wherein X is halogen, m is from 0 to 2,        m+n=3; for example, —CH₂F, —CHF₂, —CF₃, —Cl₃, or —CBr₃; and    -   ix) —SO₂R³⁰; for example, —SO₂H; —SO₂CH₃; —SO₂C₆H₅        wherein each R³⁰ is independently hydrogen, substituted or        unsubstituted C₁-C₄ linear, branched, or cyclic alkyl; or two        R³⁰ units can be taken together to form a ring comprising 3-7        atoms. However, substituents that are suitable for replacement        of a hydrogen atom are further defined herein below.

Shape Memory Polymers

The Shape Memory Polymers of the present disclosure are formed from thereaction of one or more monomers from each of the following threecategories; hydrogen bonding monomers, backbone modifying monomers, andcrosslinking monomers.

As it relates to the amount of hydrogen bonding units present in thepolymers of the present disclosure, the following three primarycategories are defined herein as:

-   -   i) lightly hydrogen bonded polymers: the initial reaction        mixture prior to polymerization comprises from about 0.5 mole        percent, mol %, to about 5 mol %, of a hydrogen bonding monomer;    -   ii) moderately hydrogen bonded polymers: the initial reaction        mixture prior to polymerization comprises from about 5 mol % to        about 10 mol %, of a hydrogen bonding monomer; and    -   iii) heavily hydrogen bonded polymers: the initial reaction        mixture prior to polymerization comprises greater than about 10        mol %, of a hydrogen bonding monomer. A first aspect of heavily        hydrogen bonded polymers relates to SMP's having from 10 mol %        to 15 mol %, of a hydrogen bonding monomer. Another aspect of        heavily hydrogen bonded polymers comprises from 15 mol % to 20        mol. %, of a hydrogen bonding monomer.

As it relates to the amount of crosslinking units present in thepolymers of the present disclosure, the following four primarycategories are defined herein as:

-   -   i) very lightly crosslinked polymers: the initial reaction        mixture prior to polymerization comprises less than about 0.5        mole percent, mol %, of a crosslinking monomer;    -   ii) lightly crosslinked polymers: the initial reaction mixture        prior to polymerization comprises from about 0.5 mole percent,        mol %, to about 1.5 mol %, of a crosslinking monomer;    -   iii) moderately crosslinked polymers: the initial reaction        mixture prior to polymerization comprises from about 1.5 mol %        to about 2.5 mol %, of a crosslinking monomer; and    -   iv) heavily crosslinked polymers: the initial reaction mixture        prior to polymerization comprises greater than about 2.5 mol %,        of a crosslinking monomer. A first aspect of heavily crosslinked        polymers relates to SMP's having from 2.5 mol % to 3.5 mol %, of        a crosslinking monomer. Another aspect of heavily crosslinked        polymers comprises from 3.0 mol % to 5 mol %, of a crosslinking        monomer.

As is disclosed further herein below, crosslinking monomer alsoencompasses monomers having a moiety which after chain formation canserve to form crosslinks between polymer chains or within a polymerchain.

Mole percent, mol %, according to the present disclosure is calculatedas in the example that follows. The three monomers:

-   -   i) a HB monomer having the formula:

-   -   ii) a MOD monomer having the formula:

-   -   iii) a XL monomer having the formula:

are admixed together prior to initiation of the polymerization reaction.The monomers have the following molecular weights respectively; HB=279.3g/mol, MOD=142.2 g/mol, and XL=338.4 g/mol. The admixture comprises thefollowing amount of each monomer:

Monomer type Mass (g) Mol % MOD 13.51 95 HB 0.56 2 XL 1.02 3

The resulting polymer from this admixture is a heavily crosslinkedpolymer as defined herein.

Hydrogen Bonding Units, HB

The shape-memory polymers of the present disclosure comprise hydrogenbonding units, HB, having the formula:

wherein each R¹ and R² is independently chosen from.

-   -   i) hydrogen;    -   ii) C₁-C₆ alkyl;    -   iii) halogen;    -   iv) cyano; and    -   v) phenyl;

R³ is chosen from:

-   -   i) hydrogen; and    -   ii) C₁-C₆ alkyl.

The formulator may chose to use a single HB unit comprising monomer whenforming the shape memory polymers of the present disclosure, or asdescribed herein below, a mixture of hydrogen bonding monomers may beused. As it relates to the shape memory polymers of the presentdisclosure, one category of polymers comprises both R¹ and R² equal tohydrogen and R³ equal to methyl. These HB units can be considered to bederivatives of methacrylic acid. A further category of polymerscomprises R¹, R², and R³ equal to hydrogen. These HB units can beconsidered to be derivatives of acrylic acid.

Q represents a unit having at least one hydrogen bond donor moiety andat least one hydrogen bond acceptor moiety. Q is further defined as aunit having the formula:

-[L]_(i)-R⁴

wherein L is a linking unit having the formula:

—[W]_(h)—[Y]_(j)-[Z]_(k)-.

When the index i is equal to 1, the linking unit L is present, however,if the index i is equal to 0, the linking unit L is absent and R⁴ isbonded directly to the polymer backbone providing a HB unit having theformula:

The expanded definition of Q, wherein the indices h, i, j, and k areeach equal to 1, has the formula:

The hydrogen bonding backbone units are incorporated into the ShapeMemory Polymers by way of HB monomers. An example of one category of HBmonomers has the formula:

which when fully expanded has the formula:

A first category of monomers relates to methacrylate-based monomershaving the general formula:

that are conveniently derived from methacrylic acid.

Another category of monomers relates to acrylate-based monomers havingthe general formula:

that are conveniently derived from acrylic acid.

As it relates to the position of the units that form the hydrogen bondsin the Q unit, it is not necessary that a hydrogen bonding acceptor orhydrogen bonding donor be present in any particular position, unit, ormoiety; this is left to the prerogative of the formulator to increaseand/or decrease the degree of potential hydrogen bond formation.

For example, in the first Category of HB units according to the presentdisclosure, hydrogen bonding donors and acceptors are found in the Zunit, as well as in the R⁴ unit. For example, the Q unit having theformula:

comprises hydrogen donors and acceptors in both the R⁴ unit, as well asthe Z unit. The categories of HB units will be set forth in detailherein below.

The units W and Z are each independently chosen from:

-   -   i) —C(O)—;    -   ii) —C(O)O—;    -   iii) —OC(O)—;    -   iv) —NH—;    -   v) —C(O)NH—;    -   vi) —NHC(O)—;    -   vii) NHC(O)NH—;    -   viii) —NHC(═NH)NH—; and    -   ix) —O—;        wherein the indices h and k are independently equal to 0 or 1.        When the index h is 0 the W unit is absent, however, when h is        equal to 1 the W unit is present. Likewise, when the index k is        equal to 0 the Z unit is absent, however, when k is equal to 1        the Z unit is present.

Y is a unit having one dr more units chosen from:

-   -   i) —(CR^(5a)R^(5b))_(s)—;    -   ii) —[(CR^(5a)R^(5b))_(v)(CR^(5a′)R^(5b′))_(u)]_(w)—;    -   ii) —[(CR^(5a)R^(5b))_(t)O]_(w)—; or    -   iii) —[(CR^(5a)R^(5b))_(t)O]_(w)(CR^(5a)R^(5b))_(s)—;        wherein each R^(5a) and R^(5b) is independently chosen from:    -   i) hydrogen;    -   ii) hydroxyl; or    -   iii) C₁-C₄ alkyl;        R^(5a′) and R^(5b′) are each independently C₁-C₄ alkyl.

The index j is 0 or 1. When the index j is 0 the Y unit is absent,however, when j is equal to 1, the Y unit is present. The indices s, t,u, v, and w are each independent of one another and are defined asfollows; the index s is from 0 to 10, the index t is from 2 to 10, theindex u is from 1 to 10, the index v is from 1 to 10, the index w isfrom 1 to 10.

The first category of Y units relates to alkylene and alkyl substitutedalkylene linking units having the formulae:

—(CR^(5a)R^(5b))_(s)— or—[(CR^(5a)R^(5b))_(v)(CR^(5a′)R^(5b′))_(u)]_(w)—

that provide for linking units comprising the same alkylene units ormixtures of different alkylene units.

The first aspect of the first category of Y units relates to Y unitsthat comprise a (C₂) alkylene linking unit thereby providing Y unitshaving the formula —CH₂CH₂— (ethylene). This unit is defined herein as Yequal to:

—(CR^(5a)R^(5b))_(s)—

wherein all R^(5a) and R^(5b) units are hydrogen and the index s isequal to 2. Ethylene units can be used to connect any of the W and Zunits described herein above. The following are non limiting examples ofcombinations of W and Z units that can be suitably combined with thisfirst category of Y units (ethylene):

The second aspect of the first category of Y units relates to C₃alkylene linking units. There are two iterations of Y units encompassedwithin the second aspect of the first category of Y units. The firstiteration relates to units wherein the index s is equal to 3 and eachR^(5a) and R^(5b) is equal to hydrogen thereby providing a propyleneunit having the formula: —CH₂CH₂CH₂—.

A non-limiting example of a Y unit comprising a propylene unit takentogether with a W unit and Z unit has the formula:

The second iteration of the second aspect of the first category of Yunits relates to units having the formula:

—[(CR^(5a)R^(5b))_(v)(CR^(5a′)R^(5b′))_(u)]_(w)—

wherein the index v is equal to 1, the index u is equal to 1, and w canhave the value from 1 to 10; R^(5a) and R^(5b) are each equal tohydrogen, R^(5a′) is methyl and R^(5b′) is hydrogen thereby providingthe following two iso-propylene units having the formulae:

—CH(CH₃)CH₂— and —CH₂CH(CH₃).

Non limiting examples of combinations of W and Z units that can besuitably combined with this second iteration of Y units include thefollowing:

-   -   i) a Y unit wherein the index w is equal to 1 includes:

-   -   ii) a Y unit wherein the index w is equal to 2 includes:

The third aspect of the first category of Y units relates to L linkingunits having the formula:

—(CR^(5a)R^(5b))_(s)—

wherein each R^(5a) and R^(5b) is equal to hydrogen and the index s isfrom 4 to 10.

The first iteration of the third aspect of the first category of Y unitsrelates to units wherein the index s is from 4 to 6, the units chosenfrom:

-   -   i) —CH₂CH₂CH₂CH₂—; (butylene)    -   ii) —CH₂CH₂CH₂CH₂CH₂—; (pentylene) and    -   iii) —CH₂CH₂CH₂CH₂CH₂CH₂—. (hexylene)

The second iteration of the third aspect of the first category of Yunits relates to units wherein the index s is from 7 to 10, the unitschosen from:

-   -   i) —CH₂CH₂CH₂CH₂CH₂CH₂CH₂—; (heptylene)    -   ii) —CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂—; (octylene)    -   iii) —CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂— (nonylene) and    -   iv) —CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂—. (decylene)

The second category of Y units relates to alkyleneoxyalkylene unitshaving the formula:

—[(CR^(5a)R^(5b))_(t)O]_(u)(CR^(5a)R^(5b))_(s)—;

wherein the first aspect of the second category of Y units encompasses(C₂) ethyleneoxy units wherein the indices s and t are both equal to 2,each R^(5a) and R^(5b) unit is hydrogen, and u is from 1 to 10.Non-limiting examples of ethyleneoxy units in combination with a W and aZ unit include the following:

A second aspect of the second category of Y units relates toalkyleneoxyalkylene units having the formula:

—[(CR^(5a)R^(5b))_(t)O]_(w)(CR^(5a)R^(5b))_(s)—;

wherein at least one R^(5a) unit of the Y unit is equal to methyl andthe remaining non-methyl R^(5a) units are hydrogen, while all the R^(5b)units present are hydrogen. This aspect, therefore, encompasses at leastone propyleneoxy (C₃) unit in the linking unit Y, non-limiting exampleswhich when taken in combination with a W and a Z unit include thefollowing:

The third category of Y units relates to units wherein at least oneR^(5a) unit in the Y unit is equal to hydroxy, for example, a Y unittaken together with a W and a Z unit having the formula:

The artisan of ordinary skill will understand that units comprising ahydroxyl can be incorporated into Y units in various ways known in theart. As a non-limiting example, the two step process:

is one method that the artisan can use to prepare a unit containing ahydroxyl unit and that can then be linked to compatible W and Z units.

R⁴ is a unit chosen from:

-   -   i) hydrogen;    -   ii) a substituted carbocyclic ring;    -   iii) a substituted aryl ring;    -   iv) a substituted or unsubstituted heterocyclic ring; or    -   v) a substituted of unsubstituted heteroaryl ring;        the substitution is a moiety capable of being a hydrogen bond        donor or a hydrogen bond acceptor. Because carbocyclic and aryl        rings do not comprise a hydrogen bond forming unit, they are        substituted with one or more units that are capable of forming a        hydrogen bond.

The first category of R⁴ units relates to substituted or unsubstitutedheterocyclic and heteroaryl rings.

The first aspect of the first category of R⁴ units relates tosubstituted or unsubstituted C₃ or C₄ heterocyclic or heteroaryl5-member rings, non-limiting examples of that are chosen from:

-   -   i) a pyrrolidinyl ring having the formula;

-   -   ii) a pyrrolyl ring having the formula:

-   -   iii) a 4,5-dihydroimidazolyl ring having the formula:

-   -   iv) an imidazolyl ring having the formula:

-   -   v) a pyrrolidinonyl ring having the formula:

-   -   vi) an imidazolidinonyl ring having the formula:

-   -   vii) an imidazol-2-only ring having the formula:

-   -   viii) an oxazolyl ring having the formula:

-   -   ix) a furanly ring having the formula:

Rings belonging to this first category of R⁴ can be substituted ringsbonded to the balance of the HB unit via a nitrogen heteroatom, forexample

the units comprising one or more hydrogen bonding moieties, for example,pyrrolidinyl units derived from proline, hydroxyproline, orhydroxypyrrolidine having the formulae:

Other rings belonging to this category can be similarly substituted, forexample,

The second aspect of the first category of R⁴ units relates tosubstituted or unsubstituted C₃, C₄ or C₅ heterocyclic or heteroaryl6-member rings, non-limiting examples of which are chosen from:

-   -   i) a morpholinyl ring having the formula:

-   -   ii) a piperidinyl ring having the formula:

-   -   iii) a pyridinyl ring having the formula:

-   -   iv) a piperazinyl ring having the formula:

-   -   v) a ketopiperazinyl ring having the formula:

-   -   vii) a dihydropyrazin2-onyl ring having the formula:

-   -   vii) a pyrazin-2-onyl ring having the formula:

-   -   viii) dihydropyrimidin-4-onyl having the formula:

-   -   viii) a uracil ring having the formula:

-   -   ix) a triazinyl ring having the formula:

Hydrogen bonding units that are readily incorporated into theshape-memory polymers of the present disclosure include:

-   -   i) 6-methylpyrimidin-4-(1H)-on-2-yl having the formula:

-   -   ii) 6-methylpyrimidin-4-(3H)-on-2-yl having the formula:

-   -   iii) 6-aminopyrimidin-4-(1H)-on-2-yl having the formula:

-   -   iv) 6-aminopyrimidin-4-(3H)-on-2-yl having the formula:

As is the case with the 5-member heterocyclic and heteroaryl rings, the6-member rings can be substituted with one or more units capable offorming a hydrogen bond.

The third aspect of the first category of R⁴ units relates tosubstituted or unsubstituted C₄, C₅, or C₆ heterocyclic or heteroaryl9-member fused rings, non-limiting examples of which are chosen from:

-   -   i) purinyl rings having the formula:

-   -   iii) amino purinyl rings having the formula:

-   -   iii) aminopurinonyl rings having the formula:

-   -   iv) pyrrolo[3,2-d]pyrimidinyl rings having the formula:

As is the case with the 5-member and 6-member heterocyclic andheteroaryl rings, the fused ring heterocyclic and heteroaryl units canbe substituted with one or more units capable of forming a hydrogenbond.

As it relates to the substitutions that can replace a hydrogen atom onthe heterocyclic or heteroaryl rings that comprise the R⁴ units of thepresent disclosure, the following is a non-limiting description.Typically the substitutions are hydrogen bond accepting or hydrogen bonddonating units, however, the alkyl units of the present disclosure arealso acceptable substitutions for hydrogen. Without being limited bytheory, the presence of alkyl substitutions may stabilize the ring orprovide for a more favorable orientation. In addition to the substitutesfor hydrogen defined herein above, the following are furthernon-limiting examples of substituents that are suitable for replacing ahydrogen atom of the R⁴ units, the units are chosen from:

-   -   i) C₁-C₄ linear or branched alkyl; for example, methyl (C₁),        ethyl (C₂), n-propyl (C₃), iso-propyl (C₃), n-butyl (C₄),        iso-butyl (C₄), sec-butyl (C₄), and tert-butyl (C₄);    -   ii) —NR^(6a)R^(6b); for example, —NH₂, —NHCH₃, —N(CH₃)₂,        —NHC₂H₅, and —N(C₂H₅)₂;    -   iii) —C(O)OR⁷; for example, —C(O)OH, —C(O)OCH₃; and —C(O)OC₂H₅;    -   iv) —C(O)R⁷; for example, —C(O)CH₃; and —C(O)C₂H₅;    -   v) —C(O)NR^(6a)R^(6b); for example, —C(O)NH₂, —C(O)NHCH₃,        —C(O)N(CH₃)₂, —C(O)NHC₂H₅, and —C(O)(C₂H₅)₂;    -   vi) —NR⁸C(O)NR^(6a)R^(6b); for example, —NHC(O)NH₂,        —NHC(O)NHCH₃, —NHC(O)N(CH₃)₂, —NHC(O)NHC₂H₅, and —NHC(O)(C₂H₅)₂;    -   vii) —NR⁸C(O)R⁷; for example, —NHC(O)CH₃, and —NHC(O)C₂H₅; and    -   viii) —NR⁸C(═NR⁸)NR^(6a)R^(6b); for example, —NHC(═NH)NH₂,        —NHC(═NH)NHCH₃, —NHC(═NH)N(CH₃)₂, —NHC(═NH)NHC₂H₅, and        —NHC(═NH)(C₂H₅)₂;        wherein R^(6a), R^(6b), R⁷, and R⁸ are each independently chosen        from hydrogen, methyl, or ethyl.

The second category of R⁴ units relates to substituted C₆ aryl (phenyl)and C₁₀ aryl (1-naphthyl and 2-naphthyl) units. The phenyl and naphthylunits that comprise the second category of R⁴ units can be substitutedwith any of the units described herein above. Non-limiting examples ofC₆ and C₁₀ substituted aryl units of the present disclosure include:3-hydroxyphenyl, 4-hydroxyphenyl, 3,5-dihydroxyphenyl, 3-methoxyphenyl,4-methoxyphenyl, 3,5-dimethoxyphenyl, 3-(dimethylamino)phenyl,4-(dimethylamino)phenyl, 3-(acetyl)phenyl, 4-(acetyl)phenyl,3-hydroxy-4-acetylphenyl, and the like.

The hydrogen bonding units of the present disclosure can be changed tofit the precise needs that are desired by the formulator. In addition tothe selection of W and Z units, as well as R⁴ units, the length of thelinking unit L can be shortened or lengthened by changing or omitting W,Y, and Z units. This lengthening or shortening of the Y unit willprovide the formulator with a method for controlling the tether to whichthe hydrogen bonding R⁴ unit is attached and, therefore, the distanceover which hydrogen bonds may be formed inter or intra molecularly. Forexample, beginning with acryloyl chloride a hydrogen bonding monomercomprising the following general formula:

can be prepared over several steps, for example, by first reactingacryloyl chloride with a protected amino alcohol:

and thereby, a simple varying of the number of —(CR^(5a)R^(5b))— unitsin the amino alcohol, will provide a method for modifying the length ofthe tether to fit the needs of the formulator. This intermediate canthen be reacted with hydrogen bonding moieties to form hydrogen bonding,HB, monomers. For example, joining the intermediate formed above with a-Z-R⁴ precursor unit:

results in a hydrogen bonding monomer wherein the Y tether can beadjusted by the choice of initial reagents, as well as the R⁴ and Zunit, to fit the variable needs of the formulator.

Another advantage of the present disclosure that the formulator can takeinto account when preparing the shape memory polymers of the presentdisclosure, is the differential rate at which hydrogen bonding unitswill “find” each other. For example, the more complex the hydrogenbonding unit, the long the time necessary for the units to locate a likehydrogen bonding unit once the elastically strained state is achieved.These more complex hydrogen bonding units will provide polymers having aslower relaxation time, but in addition, will also be provided a longerperiod of time when the polymer is initially elastically strained,wherein the formulator can make secondary adjustments to the shapememory polymer while the hydrogen bond ordering is occurring.

Backbone Modifier Units, Mod

The backbone modifier units of the present disclosure have the formula:

wherein each R^(9a), R^(9b), and R¹⁰ is independently chosen from:

-   -   i) hydrogen; or    -   ii) C₁-C₄ alkyl; methyl (C₁), ethyl (C₂), n-propyl (C₃),        iso-propyl (C₃), n-butyl (C₄), iso-butyl (C₄), sec-butyl (C₄),        and tert-butyl (C₄).        R¹¹ is a unit chosen from;    -   i) hydrogen;    -   i) C₁-C₄ linear or branched alkyl; for example, methyl (C₁),        ethyl (C₂), n-propyl (C₃), iso-propyl (C₃), n-butyl (C₄),        iso-butyl (C₄), sec-butyl (C₄), and tert-butyl (C₄);    -   ii) —NR^(12a)R^(12b); for example, —NH₂, —NHCH₃, —N(CH₃)₂,        —NHC₂H₅, —N(C₂H₅)₂, —NHC₃H₇, —N(C₃H₇)₂, —N(CH₃)(C₂H₅),        —N(CH₃)(C₃H₇), and —N(C₂H₅)(C₃H₇);    -   iii) —C(O)OR¹³; for example,        -   a) —C(O)OH;        -   b) —C(O)OCH₃;        -   c) —C(O)OCH₂CH₃;        -   d) —C(O)OCH₂CH₂CH₃;        -   e) —C(O)OCH(CH₃)₂;        -   f) —C(O)OCH₂CH₂CH₂CH₃;        -   g) —C(O)OCH₂CH₂CH₂CH₂CH₃; and        -   h) —C(O)OCH₂CH₂CH₂CH₂CH₂CH₃;    -   iv) —C(O)R¹³; for example,        -   a) —C(O)CH₃;        -   b) —C(O)CH₂CH₃;        -   c) —C(O)CH₂CH₂CH₃;        -   d) —C(O)CH(CH₃)₂;        -   e) —C(O)CH₂CH₂CH₁₂CH₃;        -   f) —C(O)CH₂CH₂CH₂CH₂CH₃; and    -   v) —C(O)NR^(12a)R^(12b); for example, —C(O)NH₂, —C(O)NHCH₃,        —C(O)N(CH₃)₂, —C(O)NHC₂H₅, and —C(O)NH(C₂H₅)₂;        wherein R^(12a), R^(12b), and R¹³ are each independently        hydrogen or C₁-C₁₀ alkyl.

As in the case of hydrogen bonding units, backbone modifier units areincorporated into the Shape Memory Polymer of the present disclosure byway of MOD monomers.

A first category of MOD monomers has the formula:

wherein R^(9a) and R^(9b) are each independently hydrogen or methyl(C₁), R¹⁰ is chosen from hydrogen, methyl (C₁) and ethyl (C₂); R¹¹ is anester or amide unit.

In a first aspect of the first category of backbone modifier unitsR^(9a) and R^(9b) are both hydrogen, R¹⁰ is methyl (C₁), and R¹¹ is anester unit having the formula C(O)OR¹³; providing a monomer having theformula:

wherein R is chosen from methyl (C₁), ethyl (C₂), n-propyl (C₃), n-butyl(C₄), n-pentyl (C₅), n-hexyl (C₆), and n-heptyl (C₇); thereby providinga backbone modifier unit having the formula:

Non-limiting examples of this embodiment include:

In a second aspect of the first category of backbone modifier unitsR^(9a) and R^(9b) are both hydrogen, R¹⁰ is methyl (C₁), R¹¹ is an amideunit having the formula —C(O)NR^(12a)R^(12b); wherein R^(12a) ishydrogen, thereby providing a backbone modifier unit having the formula:

R^(12b) is C₁-C₁₀ alkyl, inter alia, methyl (C₁), ethyl (C₂), n-propyl(C₃), n-butyl (C₄), n-pentyl (C₅), n-hexyl (C₆), and n-heptyl (C₇).Non-limiting examples of this embodiment include:

In a third aspect of the first category of backbone modifier unitsR^(9a), R^(9b), and R¹⁰ are each hydrogen and R¹¹ is an ester unithaving the formula —C(O)OR¹³; providing a monomer having the formula:

wherein R¹³ is chosen from methyl (C₁), ethyl (C₂), n-propyl (C₃),n-butyl (C₄), n-pentyl (C₅), n-hexyl (C₆), and n-heptyl (C₇); therebyproviding a backbone modifier unit having the formula:

Non-limiting examples of this embodiment include:

In a fourth aspect of the first category of backbone modifier unitsR^(9a), R^(9b), and R¹⁰ are each hydrogen and, R¹¹ is an amide unithaving the formula —C(O)NR^(12a)R^(12b); wherein R^(12a) is hydrogen,thereby providing a backbone modifier unit having the formula:

R^(12b) is C₁-C₁₀ alkyl, inter alia, methyl (C₁), ethyl (C₂), n-propyl(C₃), n-butyl (C₄), n-pentyl (C₅), n-hexyl (C₆), and n-heptyl (C₇).Non-limiting examples of this embodiment include:

Crosslinking Units, XL

The crosslinking units of the present disclosure are units that arecapable of forming a crosslink between two chains. In the first categoryof crosslinking units, the crosslink is formed between two crosslinkingunits on different chains, or sections of a single chain. In a secondcategory, crosslinking may occur between a crosslinking unit having areactive moiety and a functional group of a chain modifier unit.

The crosslinking units of the present disclosure have the formula:

wherein R^(14a), R^(14b), and R¹⁵ are each independently chosen from:

-   -   i) hydrogen; and    -   ii) C₁-C₄ alkyl; for example, methyl (C₁), ethyl (C₂), n-propyl        (C₃), iso-propyl (C₃), n-butyl (C₄), iso-butyl (C₄), sec-butyl        (C₄), and tert-butyl (C₄).

R¹⁶ units serve to connect two polymer chains or separate sections ofchains. In all the aspects of crosslinking units according to thepresent disclosure wherein two separate polymer chains are crosslinkedby a crosslinking unit, the two units once joined, R¹⁶ will have theformula:

—R¹⁷-J-R¹⁷-.

Each R¹⁷ is independently chosen from

-   -   i) —(CH₂)_(p)C(O)(CH₂)_(q)—;    -   ii) —(CH₂)_(p)C(O)O(CH₂)_(q)—;    -   iii) —(CH₂)_(p)OC(O)(CH₂)_(q)—;    -   iv) —(CH₂)_(p)NH(CH₂)_(q)—;    -   v) —(CH₂)_(p)C(O)NH(CH₂)_(q)—;    -   vi) —(CH₂)_(p)NHC(O)(CH₂)_(q)—;    -   vii) —(CH₂)_(p)NHC(O)NH(CH₂)_(q)—;    -   viii) —(CH₂)_(p)NHC(═NH)NH(CH₂)_(q)—; and    -   ix) —(CH₂)_(p)—O—(CH₂)_(q)—;        the indices p and q have the value from 0 to 10; when p is 0 the        —(CH₂)— is absent; when q is 0 the —(CH₂)— is absent;

J is a unit having the formula:

wherein R¹⁸ and R¹⁹ are each independently:

-   -   i) hydrogen;    -   ii) C₁-C₁₀ alkyl; or    -   iii) a unit capable of forming a crosslink to a third XL unit,        the unit chosen from:        -   a) —(CH₂)_(r)C(O)H;        -   b) —(CH₂)_(r)C(O)OH;        -   c) —(CH₂)_(p)OC(O)H;        -   d) —(CH₂)_(r)NH₂;        -   e) —(CH₂)_(p)C(O)NH₂;        -   f) —(CH₂)_(r)NHC(O)H;        -   g) —(CH₂)_(r)NHC(O)NH₂;        -   h) —(CH₂)_(r)NHC(═NH)NH₂;        -   i) —(CH₂)_(r)C(═CH₂)CH₃;        -   j) —(CH₂)_(r)OH; and            wherein the index r has the value from 0 to 10; when r is 0            the —(CH₂)— is absent.

As with the HB and MOD units of the present disclosure, XL units arederived from monomers that react with HB and MOD units to form a polymerbackbone. In a first category of XL units, there is a monomer thatcomprises two polymer chain forming units. The first aspect of the XLmonomers relates to units having the formula:

wherein each of the double bonds can independently react to form part ofa separate polymer chain, R¹⁶ is a unit that serves as a crosslinker.When the definition of R¹⁶ is expanded, XL monomers of the first aspectof the first category have the formula:

The following is a non-limiting example of a generic scheme that depictsthe crosslinking of a XL unit according to the first category ofcrosslinking units. In this generic example both R¹⁷ units are —C(O)O—units and J is a unit not capable of independently participating inpolymer backbone formation. The generic crosslinking unit having theformula:

is reacted with a generic HB monomer and a generic MOD monomer to form anon-limiting example of a resultant generic polymer according to thescheme herein below.

As discussed herein above, the formulator is not restricted to selectingonly one monomer from each category for preparing the shape memorypolymers of the present disclosure. For example, the scheme belowdepicts two different HB units being incorporated into a shape memorypolymer of the present disclosure.

Likewise, any mixture of monomers can be used to formulate the shapememory polymers of the present disclosure.

The second category of XL units relates to monomers that comprise a unitthat, once the polymer backbone is formed, contains a unit that canreact with a reactive species that serves to form the final crosslinkbetween two chains.

The XL monomers of the second category have the formula:

wherein R²⁰ is a unit comprising a reactive moiety capable of reactionwith a reactive moiety of a J unit precursor, for example, a unit havingthe general formula:

The reactive moieties that are suitable for undergoing reaction to forma crosslinked polymer chain include those that are capable of reactingunder typical polymerization condition, inter alia, thermal, freeradical, photo reaction, and cationic or anionic polymerization.

The artisan of ordinary skill will realize the reactive moieties of thepolymer chain will in many instances be different from the reactivemoiety that comprises the J unit precursor. As a non-limiting example, abis-alcohol linking unit precursor can be reacted with a polymer chaincomprising methacrylic acid units to form crosslinks as depicted hereinbelow:

A further category of XL cross-linking units relates to photocrosslinking units, for example, units that are capable of formingcrosslinks between two polymer chains when exposed to electromagneticradiation, i.e., UV light. Shape Memory Polymers comprising photocrosslinking units can be cured by exposure to UV radiation. By varyingthe exposure time and light intensity the formulator can control theamount of crosslinking present.

The formulator can, by using this method of crosslinking, have anadmixture of non-crosslinked copolymers that is a liquid and crosslinkthe polymer to form a solid or non-flowable crosslinked shape memorypolymer. The formulator can make use of this embodiment by pouring theadmixture of linear copolymers into a mold or other shape formingcontainer, applying UV light, and thereby obtain the shape memorypolymer in a desire form. Or in an alternative, a viscous solution oflinear copolymers can be drawn out under UV radiation to form longthreads or wires of shape memory polymers. An iteration of thisembodiment is to draw out the shape memory polymers that can becrosslinked at two different UV wavelengths, wherein one wavelength ismore reactive. In this way a partially crosslinked polymer can be drawnout at a first wavelength of UV radiation, formed into a desiredconfiguration, then full crosslinked by UV radiation at a secondwavelength.

One non-limiting example of photo crosslinking units is the monomercomprising a coumarin unit, the monomer having the formula:

wherein R^(14a), R^(14b), R¹⁵, and the index p are defined herein above.

The Shape Memory Polymers of the present disclosure are formed byreacting under suitable conditions, three types of monomers;

-   -   a) from about 0.5 to about 5 mol % of a monomer having the        formula:

-   -   b) from about 90 to about 99 mol % of a monomer having the        formula:

-   -   c)        -   i) from about 0.5 to about 5 mol % of a monomer having the            formula:

-   -   -   ii) from about 0.5 to about 5 mol % of a monomer having the            formula:

wherein R²⁰ is a reactive moiety capable of either:

-   -   a) reacting directly with another R²⁰ unit of a second polymer        chain to form a R¹⁶ crosslinking unit; or    -   b) two R²⁰ units from two polymer chains are capable of reacting        with a molecule that comprises two reactive groups capable of        reacting with both R²⁰ units to form a R¹⁶ crosslinking unit.

A first category of polymers relates to reaction of:

-   -   a) from about 0.5 to about 5 mol % of one or more monomers        having the formula:

-   -   b) from about 90 to about 99 mol % of one or more monomers        having the formula:

-   -   c) from about 0.5 to about 5 mol % of one or more monomers        having the formula:

wherein each crosslinking monomer comprises a unit on two separatechains.

For example the generic monomer represented by the formula:

wherein the value for the index x (HB unit) is 5, the value for theindex y (MOD unit) is 90, and the value for the index z (XL unit) is 5,as prepared by combining 5 mol % of a HB unit, 90 mol % of a MOD unitand 5 mol % of a crosslinking unit. This polymer would be represented bythe following formula:

—[HB]₅-[MOD]₉₀-[XL]₅-.

A second category of polymers relates to reaction of:

-   -   a) from about 0.5 to about 5 mol % of one or more monomers        having the formula:

-   -   b) from about 90 to about 99 mol % of one or more monomers        having the formula:

-   -   c) from about 0.5 to about 5 mol % of one or more monomers        having the formula:

to form shape-memory polymer precursors in the form of linear polymericchains that are then subsequently crosslinked, wherein R²⁰ comprises areactive moiety that forms crosslinks after the polymer backbones areformed.

R²⁰ is a reactive moiety that is capable of reacting with anintermediate such that two R²⁰ units from two separate polymer chainsreact with the intermediate to form a crosslink between two polymerchains. A first iteration encompasses R²⁰ units chosen from:

-   -   i) —C(O)OR²¹;    -   ii) —NCO; and    -   iii) —N₃;        wherein R²¹ is hydrogen or C₁-C₄ linear or branched alkyl.

In addition, the R²⁰ units described herein above have reactive unitscapable of reacting with a di-functional molecule to form a shape memorypolymer according to the present disclosure, the di-functional moleculehas the formula:

R²²-J-R²²

R²² each is independently chosen from

-   -   i) ClC(O)(CH₂)_(b)—;    -   ii) Cl(CH₂)_(b)—;    -   iii) H₂N(CH₂)_(b)—;    -   iv) HOC(O)(CH₂)_(b)—;    -   v) HO(CH₂)_(b)—;    -   vi) OCN(CH₂)_(b)—; and    -   vii) N₃(CH₂)_(b)═;

the index b is from 1 to 10.

A non-limiting example of this aspect includes shape memory polymerprecursor chains having a —C(O)OH reactive moiety, for example:

are treated with 1,8-dihydroxyoctane to form a shape memory polymer:

The following scheme shows the process for forming shape memory polymersof the present disclosure wherein the crosslinking is done after thepolymer backbone is formed.

The first step involves forming linear polymer chains, for example,polymer chain formation produces a linear, crosslinkable backbone asdepicted below, wherein RM represents a reactive moiety:

After backbone formation, the polymer is reacted with a compound thatcontains reactive moieties that can be used to crosslink the linearchains and thereby form a shape memory polymer.

The following is a non-limiting generic example wherein a reactivemoiety is added to a polymer backbone after which the polymer can becrosslinked by photo-crosslinking methods using UV radiation and aphotoacid generator.

In a third category, the crosslinking monomer may comprise a reactiveunit in such a manner that when after the polymer backbones are formed,the formulator may then crosslink the chains to form the final polymeras depicted in the following scheme:

wherein the crosslinking may be accomplished by the use of a chemicalreagent, or the formulator may take advantage of special reactionconditions that forms the crosslink.

The compounds that can react with the R²⁰ moieties and therefore be usedto form the crosslinks, are any compounds capable of reaction with theunits to form a J unit as defined herein above.

Non-limiting examples include:

i) R²⁰ units that are —C(O)OH reacting with di-alcohols having theformulae HO(CH₂)_(n)OH wherein n is from 2 to 20, to form crosslinkshaving the formulae:

—C(O)O(CH₂)_(n)OC(O)—;

ii) R²⁰ units that are —C(O)OH reacting with di-amines having theformulae H₂N(CH₂)_(n)NH₂ wherein n is from 2 to 20, to form crosslinkshaving the formulae:

—C(O)NH(CH₂)_(n)NHC(O)—; and

iii) R²⁰ units that are —NCO reacting with di-amines having the formulaeH₂N(CH₂)_(n)NH₂ wherein n is from 2 to 20, to form crosslinks having theformulae:

—NHC(O)NH(CH₂)_(n)NHC(O)NH—.

Preparation of Polymers

Schemes I-III and Examples 1-3 herein below provide examples of thepreparation of a hydrogen bonding unit, HB, monomers according to thepresent disclosure.

EXAMPLE 1 3-Oxo-3-(pyridin-2-ylamino)propyl acrylate (2)

Preparation of 3-chloro-3-oxopropyl acrylate (1): 2-Carboxyethylacrylate (1 eq.) is dissolved in CH₂Cl₂ and the solution is cooled in anice bath. Thionyl chloride (1 eq.) is added dropwise and the mixture isallowed to warm to room temperature and stir for 4 hours. The solvent isremoved under reduced pressure and the desired product is isolated byvacuum distillation.

Preparation of 3-oxo-3-(pyridin-2-ylamino)propyl acrylate (2):3-Chloro-3-oxopropyl acrylate, 1, (1 eq.), 2-aminopyridine (1 eq.) andtriethylamine (3 eq.) are dissolved in toluene at 0° C. A few crystalsof hydroquinone is added to inhibit any polymerization side reactions.The solution is allowed to stir approximately 18 hours at a temperaturefrom about 0° C. to room temperature. The solvent is removed underreduced pressure and the crude material purified over silica. For a moredetailed account of this procedure See M. A. Diab, A. Z. El-Sonbati, A.A. El-S anabori, F. I. Taha, Polymer Degrad. Stab. 1989, 24, 51,included herein by reference.

EXAMPLE 2 2-[3-(6-Methyl-4-oxo-1,4-dihydropyridin-2-yl)ureido]ethylmethacrylate (5)

Preparation of 2-amino methacrylate (3): A mixture of ethanolaminehydrochloride (1 eq.), thionyl chloride (1 eq.) and a catalytic amountof Cu powder are heated together to 100° C. Over the next 2 hoursmethylacrylolyl chloride (2 eq.) is added after which the mixture iscooled to approximately 60° C. and ethyl acetate is added. Crystals maybegin to form as the solution cools. The crude product is recrystallizedfrom ethyl acetate/isopropanol to afford the desired product. For a moredetailed account of this procedure See J. M. Geurts, C. M. Gottgens, M.A. I. Van Graefschepe, et al., J. of Applied Polymer Science, 2001, 80,1401 included herein by reference.

Preparation ofN-(6-methyl-4-oxo-1,4-dihydropyrimidin-2-yl)-1H-imidazole-1-carboxamide(4): A mixture of 6-methylisocytosine (1 eq.) and carbonyldiimidazole(1.5 eq.) were combined in dimethylsulfoxide (DMSO) and the solution wasstirred at 60° C. for 2 hours. The mixture was cooled to about roomtemperature and acetone added after which the desired productprecipitated as a white powder that was collected by filtration. Theprocedure of A. T. Cate, P. Y. W. Dankers, H. Kooijman, A. L. Spek, R.P. Sijbesma, and E. W. Meijer, J. of Am. Chem. Soc., 2003, 125, 6860 wasfollowed for this step. The product can be used without furtherpurification.

Preparation of 2-[3-(6-methyl-4-oxo-1,4-dihydropyridin-2-yl)ureido]ethylmethacrylate (5): To a solution of 2-amino methacrylate hydrochloride,3, (1 eq.) and triethylamine (1 eq.) in chloroform (30 mL) is addedN-(6-methyl-4-oxo-1,4-dihydropyrimidin-2-yl)-1H-imidazole-1-carboxamide,4, (1 eq.). The reaction mixture is stirred for 4 hours at 50° C. andthe solvent is removed under reduced pressure. The residue is purifiedover silica, and the product was obtained by precipitation in methanol.For a more detailed description See A. T. Cate, P. Y. W. Dankers, H.Kooijman, A. L. Spek, R. P. Sijbesma, and E. W. Meijer, J. of Am. Chem.Soc., 2003, 125, 6860 include herein by reference.

EXAMPLE 31-(4-Methyl-3-oxopeny-4-enyl)-3-(6-methyl-4-oxo-1,4-dihydropyridin-2-yl)urea[UPy-EA] (6)

Preparation of1-(4-Methyl-3-oxopeny-4-enyl)-3-(6-methyl-4-oxo-1,4-dihydropyridin-2-yl)urea[UPy-EA] (6): The procedure of K. Yamauchi; J. R. Lizotte; T. E. Long.Macromolecules 2003, 36, 1083-1088, included herein by reference, wasfollowed for the preparation of the title compound, that is summarizedherein below. 6-Methylisocytosine (1.25 g, 10.0 mmol) was dissolved inDMSO (10 mL) at 130° C., 2-isocyanatoethyl methacrylate (available fromAldrich Chemical Co.) (1.70 g, 11.0 mmol) was added. In less than 1 min,the mixture was quenched by a water bath. The precipitated white solidwas filtered and washed with hexane. Yield ˜70%.

The following Scheme IV and Example 4 illustrate the preparation of ashape memory polymer according to the present disclosure.

EXAMPLE 4 [Butyl acrylate]_(96.5)[trimethylolpropanetrimethacrylate]_(1.5)-[UPy-EA]_(2.0)

Preparation of [Butyl acrylate]_(96.5)-[trimethylolpropanetrimethacrylate]_(1.5)[UPy-EA]_(2.0) (7): To a reaction vessel wascharged butyl acrylate (96.5 mol %), trimethylol-propane trimethacrylate(1.5 mol %), and1-(4-Methyl-3-oxopeny-4-enyl)-3-(6-methyl-4-oxo-1,4-dihydropyridin-2-yl)urea,7, (2.0 mol %) were combined with N-methyl-pyrrolidinone (50% by wt.) atroom temperature. Nitrogen gas was bubbled through the reaction mixturefor 30 minutes. Azobisisobutylnitrile [AIBN] (1.0 mmol) was added andthe reaction mixture injected onto a Petri dish inside a custom builtgas-tight, bell-jar apparatus. The temperature of the reaction wascontrolled at 65° C. while the reaction apparatus was continuouslypurged with nitrogen during the course of the reaction. After 12 hoursthe reaction apparatus is cooled and the resulting shape memory polymeris dried for 48 hours.

The following is an example of another iteration of the polymer outlinedin Scheme IV.

EXAMPLE 5 [Butyl acrylate]_(97.5)[trimethylolpropanetrimethacrylate]_(1.5) [UPy-EA]_(1.0)

Preparation of [Butyl acrylate]_(96.5)-[trimethylolpropanetrimethacrylate]_(1.5)[UPy-EA]_(2.0) (7): To a reaction vessel wascharged butyl acrylate (97.5 mol %), trimethylol-propane trimethacrylate(1.5 mol %), and1-(4-Methyl-3-oxopeny-4-enyl)-3-(6-methyl-4-oxo-1,4-dihydropyridin-2-yl)urea,7, (1.0 mol %) were combined with N-methyl-pyrrolidinone (50% by wt.) atroom temperature. Nitrogen gas was bubbled through the reaction mixturefor 30 minutes. Azobisisobutylnitrile [AIBN] (1.0 mmol) was added andthe reaction mixture injected onto a Petri dish inside a custom builtgas-tight, bell-jar apparatus. The temperature of the reaction wascontrolled at 65° C. while the reaction apparatus was continuouslypurged with nitrogen during the course of the reaction. After 12 hoursthe reaction apparatus is cooled and the resulting shape memory polymeris dried for 48 hours.

The following are non-limiting examples of shape memory polymersaccording to the present disclosure.

1^(st) Iteration HB monomer Q moiety R⁴ CH₂═C(CH₃)Q —CO₂(CH₂)₂NHC(O)NHR⁴6-methylpyrimidin-4-(1H)-on-2-yl MOD monomer R¹¹ R¹³ CH₂═CHR¹¹ —CO₂R¹³n-butyl XL monomer R¹⁶ J CH₂═C(CH₃)R¹⁶ —C(O)OCH₂JCH₂OC(O)——C(C₂H₅)[CH₂O₂CC(═CH₂)CH₃]— No. MOD mol % HB mol % XL mol % 1 96.5 1.02.5 2 97.0 1.0 2.0 3 96.5 2.0 1.5 4 97.0 2.0 1.0

2^(nd) Iteration HB monomer Q moiety R⁴ CH₂═C(CH₃)Q —CO₂(CH₂)₃NHC(O)NHR⁴6-methylpyrimidin-4-(1H)-on-2-yl MOD monomer R¹¹ R¹³ CH₂═CHR¹¹ —CO₂R¹³n-butyl XL monomer R¹⁶ J CH₂═C(CH₃)R¹⁶ —C(O)OCH₂JCH₂OC(O)——C(C₂H₅)[CH₂O₂CC(═CH₂)CH₃]— No. MOD mol % HB mol % XL mol % 5 96.5 1.02.5 6 97.0 1.0 2.0 7 96.5 2.0 1.5 8 97.0 2.0 1.0

3^(rd) Iteration HB monomer Q moiety R⁴ CH₂═C(CH₃)Q —CO₂(CH₂)₄C(O)NHR⁴6-methylpyrimidin-4-(1H)-on-2-yl MOD monomer R¹¹ R¹³ CH₂═CHR¹¹ —CO₂R¹³n-butyl XL monomer R¹⁶ J CH₂═C(CH₃)R¹⁶ —C(O)OCH₂JCH₂OC(O)——C(C₂H₅)[CH₂O₂CC(═CH₂)CH₃]— No. MOD mol % HB mol % XL mol %  9 96.5 1.02.5 10 97.0 1.0 2.0 11 96.5 2.0 1.5 12 97.0 2.0 1.0

4^(th) Iteration HB monomer Q moiety R⁴ CH₂═C(CH₃)Q —CO₂(CH₂)₂C(O)NHR⁴6-methylpyrimidin-4-(1H)-on-2-yl MOD monomer R¹¹ R¹³ CH₂═CHR¹¹ —CO₂R¹³n-butyl XL monomer R¹⁶ J CH₂═C(CH₃)R¹⁶ —C(O)OCH₂JCH₂OC(O)——C(C₂H₅)[CH₂O₂CC(═CH₂)CH₃]— No. MOD mol % HB mol % XL mol % 13 96.5 1.02.5 14 97.0 1.0 2.0 15 96.5 2.0 1.5 16 97.0 2.0 1.0

5^(th) Iteration HB monomer Q moiety R⁴ CH₂═C(CH₃)Q —CO₂(CH₂)₂NHC(O)NHR⁴pyridin-2-yl MOD monomer R¹¹ R¹³ CH₂═CHR¹¹ —CO₂R¹³ n-butyl XL monomerR¹⁶ J CH₂═C(CH₃)R¹⁶ —C(O)OCH₂JCH₂OC(O)— —C(C₂H₅)[CH₂O₂CC(═CH₂)CH₃]— No.MOD mol % HB mol % XL mol % 17 96.5 1.0 2.5 18 97.0 1.0 2.0 19 96.5 2.01.5 20 97.0 2.0 1.0

6^(th) Iteration HB monomer Q moiety R⁴ CH₂═C(CH₃)Q —CO₂(CH₂)₃NHC(O)NHR⁴pyridine-2-yl MOD monomer R¹¹ R¹³ CH₂═CHR¹¹ —CO₂R¹³ n-butyl XL monomerR¹⁶ J CH₂═C(CH₃)R¹⁶ —C(O)OCH₂JCH₂OC(O)— —C(C₂H₅)[CH₂O₂CC(═CH₂)CH₃]— No.MOD mol % HB mol % XL mol % 21 96.5 1.0 2.5 22 97.0 1.0 2.0 23 96.5 2.01.5 24 97.0 2.0 1.0

7^(th) Iteration HB monomer Q moiety R⁴ CH₂═C(CH₃)Q —CO₂(CH₂)₄C(O)NHR⁴pyridin-2-yl MOD monomer R¹¹ R¹³ CH₂═CHR¹¹ —CO₂R¹³ n-butyl XL monomerR¹⁶ J CH₂═C(CH₃)R¹⁶ —C(O)OCH₂JCH₂OC(O)— —C(C₂H₅)[CH₂O₂CC(═CH₂)CH₃]— No.MOD mol % HB mol % XL mol % 25 96.5 1.0 2.5 26 97.0 1.0 2.0 27 96.5 2.01.5 28 97.0 2.0 1.0

8^(th) Iteration HB monomer Q moiety R⁴ CH₂═C(CH₃)Q —CO₂(CH₂)₂C(O)NHR⁴pyridin-2-yl MOD monomer R¹¹ R¹³ CH₂═CHR¹¹ —CO₂R¹³ n-butyl XL monomerR¹⁶ J CH₂═C(CH₃)R¹⁶ —C(O)OCH₂JCH₂OC(O)— —C(C₂H₅)[CH₂O₂CC(═CH₂)CH₃]— No.MOD mol % HB mol % XL mol % 29 96.5 1.0 2.5 30 97.0 1.0 2.0 31 96.5 2.01.5 32 97.0 2.0 1.0

Thermal-mechanical analysis experiments were conducted on the ShapeMemory Polymer of Example 4. Experimental data showing typical shapememory responses are shown in FIG. 5. On the left, the solid lineindicates percent strain. The sample is initially deformed(approximately 22% strain) at 60° C. using a 50 mN (10 kPa) load. Whileunder load, the temperature (dotted line) is reduced to approximately 5°C., and then the load (dotted line) is removed. The sample is “pinned”in its temporary shape, but slowly recovers. The rate of recovery isaccelerated by increasing temperature. Polymers without associatingside-groups behave as nearly ideal elastomers. The number of associatingside groups present in the polymer influences the time-temperaturedependence of shape recovery. To further illustrate this fact, the creepcompliance of this polymer is in FIG. 6. The sample is isothermallyloaded with a 50 mN load at various temperatures. The data can becollapsed onto a master curve using an appropriate shift factor. Thesedata demonstrate an elastomeric network that is functionalized with areversibly associating side-group whereby the material has nocrystallinity and is well above its glass transition. The architectureof the presently disclosed polymers enables precise fine-tuning ofphysical properties.

When the disclosed polymers are elastically deformed at a shape memorytemperature T_(SM) and subsequently lowered to a shape memorytemperature, T_(F), and the method by which the polymer is elasticallydeformation is removed, the polymer returns to its original shape at arecovery rate, R_(REC), that is inversely related to the difference inthe temperature, ΔT_(DEF), wherein ΔT_(DEF)=T_(SM)−T_(F).

The recovery rate of the shape memory polymers disclosed herein are notalways linear over time or over temperature. The formulator can takeadvantage of this differential recovery rate. In one instance, theformulator can utilize an initial slow shape recovery for embodimentswherein the user needs some amount of time to position and/or adjust theposition of the distended polymer. Likewise, in another embodiment, aninitial quick recovery rate will allow the polymer to function, forexample, in controlling the bleeding of an artery, whereas the slowerlate recovery rate allows the user to finely adjust the position of thepolymer or to cut away unused or unnecessary portions.

The percent strain recovery, Δ_(REC), at any point along the recoverycurve is defined herein as:

Δ_(STRAIN) =S _(i) −S _(t)

wherein S_(i) is the initial percent strain and S_(t) is the percentstrain at time t. Using the solid line curve in FIG. 5, the initialpercent strain, S_(i), is approximately 22% at 50 minutes and thepercent strain at about 120 minutes, S₁₂₀, is approximately 17%.Therefore the Δ_(STRAIN) is 5% at 120 minutes. This corresponds to thepolymer recovering approximately 23% of its original form in 70 minutes.Therefore, the rate of recovery over this portion of the curve isapproximately 0.33%/minute. Considering the balance of the curve fromtime 120 minutes to about 140 minutes, the recovery rate over thisportion of the curve is approximately 3.9%/minute. The formulator cantake advantage of this differential rate of recovery. By manipulation ofthe polymer backbone and number of crosslinking units, the formulatorcan adjust the recovery rate to suit any particular application.

The shape memory polymers of the present disclosure have an overallrecovery rate, R_(REC), of from about 0.001%/minute to about100%/minute. One embodiment of the polymers disclosed herein have anoverall R_(REC) of from about 0.05%/minute to about 20%/minute. Inanother embodiment, the polymers disclosed herein have a R_(REC) of fromabout 0.1%/minute to about 10%/minute. In a further embodiment, thepolymers disclosed herein have a R_(REC) of from about 0.5%/minute toabout 10%/minute. In still another embodiment, the polymers disclosedherein have a R_(REC) of from about 1%/minute to about 20%/minute. Inyet another embodiment, the polymers disclosed herein have a R_(REC) offrom about 5%/minute to about 20%/minute.

The shape memory polymers can also have overall recovery rates thatinclude variable recovery rates for portions of the recovery cycle, forexample a portion of the overall recovery rate that is slower than theoverall recovery rate. In one embodiment of a slower recovery rate, therecovery rate, R_(REC), over at least 10% of the recovery curve, is fromabout 0.001%/minute to about 5%/minute. In another embodiment of aslower recovery rate, the recovery rate, R_(REC), over at least 10% ofthe recovery curve, is from about 0.01%/minute to about 1%/minute. Inyet another embodiment of a slower recovery rate, the recovery rate,R_(REC), over at least 10% of the recovery curve, is from about0.1%/minute to about 1%/minute.

The shape memory polymers can also have a faster variable recovery ratesfor portions of the recovery cycle, for example a portion of the overallrecovery rate that is faster than the overall recovery rate. In oneembodiment of a faster recovery rate, the recovery rate, R_(REC), overat least 10% of the recovery curve, is from about 1%/minute to about100%/minute. In another embodiment of a faster recovery rate, therecovery rate, R_(REC), over at least 10% of the recovery curve, is fromabout 5%/minute to about 75%/minute. In yet another embodiment of afaster recovery rate, the recovery rate, R_(REC), over at least 10% ofthe recovery curve, is from about 10%/minute to about 50%/minute.

The shape memory polymers of the present invention can be used to formbiocompatible devices. For example, shape memory polymers can be used informing hearing protection. An ear plug formed from a SMP can bedeformed at room temperature to over 100% strain, and it returns to itsoriginal shape on the order of several minutes after insertion into theear thereby closing the ear channel and offering a tight, sound reducingear plug.

Because the human body has a relatively constant temperature, SMP's thathave a specific form at body temperature can be elastically deformed ata higher temperature, inserted into the human body, and then returned totheir original shape or configuration once equilibrated with the body'stemperature. Non-limiting examples of medical uses include stents,sutures, vascular compresses, vascular clips, and the like.

While particular embodiments of the present invention have beenillustrated and described, it would be obvious to those skilled in theart that various other changes and modifications can be made withoutdeparting from the spirit and scope of the invention. It is thereforeintended to cover in the appended claims all such changes andmodifications that are within the scope of this invention.

1. A polymer having the formula:—[HB]_(x)-[MOD]_(y)-[XL]_(z)- comprising: i) hydrogen bonding units, HB,having at least one hydrogen bond donor moiety and at least one hydrogenbond acceptor moiety; ii) backbone modifier units, MOD; and iii)crosslinking units, XL, that are capable of forming one or morecrosslinks; the indices x, y, and z represent the mole fraction of eachunit, the index x is from about 0.1 to about 20, the index y is fromabout 75 to about 99.8, and the index z is from about 0.1 to about 5;wherein the polymer is characterized by having a shape memorytemperature, T_(SM), such that the polymer can be elastically deformedat the shape memory temperature, and subsequently lowered to a shapememory freezing temperature, T_(F), and the method of elasticdeformation is removed, the polymer will return to its original shapewith a rate slower than the rate observed if the method of mechanicalelastic deformation were removed at T_(SM); provided the shape memoryfreezing temperature T_(F) is above the glass transition, T_(G), of thepolymer, and provided the polymer is in the amorphous state at T_(F). 2.A polymer according to claim 1, wherein when the polymer is elasticallydeformed at a shape memory temperature T_(SM) and subsequently loweredto a shape memory temperature, T_(F), and the method by which thepolymer is elastically deformation is removed, the polymer returns toits original shape at an overall recovery rate, R_(REC), and whereinfurther the recovery rate is inversely related to the difference in thetemperature, ΔT_(DEF), wherein ΔT_(DEF)=T_(SM)−T_(F).
 3. A polymeraccording to claim 2, wherein the overall R_(REC) is from about0.001%/minute to about 100%/minute.
 4. A polymer according to claim 3,wherein the overall R_(REC) is from about 0.05%/minute to about20%/minute.
 5. A polymer according to claim 4, wherein the overallR_(REC) is from about 0.1%/minute to about 10%/minute.
 6. A polymeraccording to claim 5, wherein the overall R_(REC) is from about0.5%/minute to about 10%/minute.
 7. A polymer according to claim 6,wherein the overall R_(REC) is from about 1%/minute to about 20%/minute.8. A polymer according to claim 7, wherein the overall R_(REC) is fromabout 5%/minute to about 20%/minute.
 9. A polymer according to claim 2,wherein the overall recovery rate includes a variable recovery rate overat least 10% of the recovery rate that is from about 0.001%/minute toabout 5%/minute.
 10. A polymer according to claim 9, wherein thevariable recovery rate is from about 0.01%/minute to about 1%/minute.11. A polymer according to claim 10, wherein the variable recovery rateis from about 0.1%/minute to about 1%/minute.
 12. A polymer according toclaim 2, wherein the overall recovery rate includes a variable recoveryrate over at least 10% of the recovery rate that is from about 1%/minuteto about 100%/minute.
 13. A polymer according to claim 12, wherein theoverall recovery rate includes a variable recovery rate over at least10% of the recovery rate that is from about 5%/minute to about75%/minute.
 14. A polymer according to claim 13, wherein the overallrecovery rate includes a variable recovery rate over at least 10% of therecovery rate that is from about 10%/minute to about 50%/minute.
 15. Apolymer according to claim 1, wherein the HB unit has the formula:

wherein each R¹ and R² is independently chosen from: i) hydrogen; ii)C₁-C₆ alkyl; iii) halogen; iv) cyano; and v) phenyl; R³ is chosen from:i) hydrogen; and ii) C₁-C₆ alkyl; and Q is a unit having at least onehydrogen bond donor moiety or at least one hydrogen bond acceptormoiety; the index m is from 1 to
 4. 16. A polymer according to claim 15,wherein Q has the formula:-[L]_(i)-R⁴ wherein when the index i is equal to 1, the linking group Lis present, when the index i is equal to 0 the linking unit is absent; Lis a linking unit having the formula:—[W]_(h)—[Y]_(j)-[Z]_(k)- W and Z are each independently chosen from: i)—C(O)—; ii) —C(O)O—; iii) —OC(O)—; iv) —NH—; v) —C(O)NH—; vi) —NHC(O)—;vii) —NHC(O)NH—; viii) —NHC(═NH)NH—; and ix) —O—; the indices h and kare independently equal to 0 or 1; when h is 0 the W unit is absent,when h is 1 the W unit is present; when k is 0 the W unit is absent,when k is 1 the W unit is present; Y is a unit having one or more unitschosen from: i) —(CR^(5a)R^(5b))_(s)—; ii)—[(CR^(5a)R^(5b))_(v)(CR^(5a′)R^(5b′))_(u)]_(w)—; ii)—[(CR^(5a)R^(5b))_(t)O]_(w)—; or iii)—[(CR^(5a)R^(5b))_(t)O]_(w)(CR^(5a)R^(5b))_(s)—; each R^(5a) and R^(5b)is independently chosen from: i) hydrogen; or ii) C₁-C₄ alkyl; R^(5a′)and R^(5b′) are each independently C₁-C₄ alkyl; the index j is 0 or 1;when j is equal to 0 the Y unit is absent, when j is equal to 1 the Yunit is present; the index s is from 0 to 10, the index t is from 2 to10, the index u is from 1 to 10, the index v is from 1 to 10, the indexw is from 1 to 10; R⁴ is a unit chosen from: i) hydrogen; ii) asubstituted carbocyclic ring; iii) a substituted aryl ring; iv) asubstituted or unsubstituted heterocyclic ring; or v) a substituted ofunsubstituted heteroaryl ring; the substitution is a moiety capable ofbeing a hydrogen bond donor or a hydrogen bond acceptor.
 17. A polymeraccording to claim 16, wherein R⁴ is a substituted or unsubstituted C₃or C₄ heterocyclic or heteroaryl ring chosen from: i) a pyrrolidinylring having the formula;

ii) a pyrrolyl ring having the formula:

iii) a 4,5-dihydroimidazolyl ring having the formula:

iv) an imidazolyl ring having the formula:

v) a pyrrolidinonyl ring having the formula:

vi) an imidazolidinonyl ring having the formula:

vii) an imidazol-2-only ring having the formula:

viii) an oxazolyl ring having the formula:

ix) a furanly ring having the formula:


18. A polymer according to claim 16, wherein R⁴ is a substituted, orunsubstituted C₃, C₄, or C₅ heterocyclic or heteroaryl ring chosen from:i) a morpholinyl ring having the formula:

ii) a piperidinyl ring having the formula:

iii) a pyridinyl ring having the formula:

iv) a piperazinyl ring having the formula:

v) a ketopiperazinyl ring having the formula:

vi) a dihydropyrazin2-onyl ring having the formula:

vii) a pyrazin2-onyl ring having the formula:

viii) dihydropyrimidin-4-onyl having the formula:

ix) a uracil ring having the formula:

x) a triazinyl ring having the formula:


19. A polymer according to claim 16, wherein R⁴ is a substituted orunsubstituted C₅ or C₆ heterocyclic or heteroaryl ring chosen from: i)purinyl rings having the formula:

iv) amino purinyl rings having the formula:

iii) aminopurinonyl rings having the formula:

iv) pyrrolo[3,2-d]pyrimidinyl rings having the formula:


20. A polymer according to claim 1 wherein the R⁴ unit is a C₃, C₄ or C₅heterocyclic or heteroaryl ring substituted with one or more unitschosen from: i) C₁-C₄ linear or branched alkyl; ii) —NR^(6a)R^(6b); iii)—C(O)OR⁷; iv) —C(O)R⁷; v) —C(O)NR^(6a)R^(6b); vi) —NR⁸C(O)NR^(6a)R^(6b);vii) —NR⁸C(O)R⁷; and viii) —NR⁸C(═NR⁸)NR^(6a)R^(6b); R^(6a), R^(6b), R⁷,and R⁸ are each independently chosen from hydrogen, methyl or ethyl. 21.A polymer according to claim 1, wherein R⁴ has the formula:


22. A polymer according to claim 1, wherein Y has the formula:—(CR^(5a)R^(5b))_(s)— each R^(5a) is independently chosen from hydrogenor methyl, R^(5b) is hydrogen, the index s is from 2 to
 6. 23. A polymeraccording to claim 22, wherein Y is a unit chosen from: i) —CH₂CH₂—; ii)—CH₂CH₂CH₂—; iii) —CH(CH₃)CH₂—; iv) —CH₂CH(CH₃)—; v) —CH₂CH₂CH₂CH₂—; vi)—CH₂CH₂CH₂CH₂CH₂—; and vii) —CH₂CH₂CH₂CH₂CH₂CH₂—.
 24. A polymeraccording to claim 23, wherein Y is —CH₂CH₂— (ethylene).
 25. A polymeraccording to claim 1, wherein Y has the formula:—[(CR^(5a)R^(5b))₂O]_(w)(CR^(5a)R^(5b))₂— R^(5a) and R^(5b) are eachindependently hydrogen or methyl; the index w is from 1 to
 4. 26. Apolymer according to claim 25, wherein Y has the formula:—[CH₂CH₂O]_(w)CH₂CH₂—.
 27. A polymer according to claim 1, wherein Y hasthe formula:[(CR^(5a)R^(5b))₂O]_(w)(CR^(5a)R^(5b))₂— wherein R^(5a) is hydrogen ormethyl provided at least one R^(5a) unit is methyl; R^(5b) is hydrogen;the index w is from 1 to
 4. 28. A polymer according to claim 1, whereinlinking unit L has the formula chosen from: i)


29. A polymer according to claim 1, wherein the MOD unit has theformula:

wherein each R^(9a), R^(9b), and R¹⁰ are independently chosen from: i)hydrogen; or ii) C₁-C₄ alkyl; R¹¹ is a unit chosen from; i) hydrogen; i)C₁-C₄ linear or branched alkyl; ii) —NR^(12a)R^(12b); iii) —C(O)OR¹³;iv) —C(O)R¹³; and v) —C(O)NR^(12a)R^(12b); wherein R^(12a), R^(12b), andR¹³ are each independently hydrogen or C₁-C₁₀ alkyl.
 30. A polymeraccording to claim 29, wherein R^(9a) and R^(9b) are both hydrogen. 31.A polymer according to claim 29, wherein R¹⁰ is hydrogen or methyl. 32.A polymer according to claim 29, wherein R¹¹ has the formula —C(O)OR¹³.33. A polymer according to claim 32, wherein R¹³ is chosen from methyl,ethyl, n-propyl, n-butyl, n-pentyl, and n-hexyl.
 34. A polymer accordingto claim 1, wherein the XL unit has the formula:

wherein the index n is from 1 to 4; R^(14a), R^(14b), and R¹⁵ are eachindependently chosen from: ii) hydrogen; and ii) C₁-C₄ alkyl; R¹⁶ hasthe formula:—R¹⁷-J-R¹⁷— each R¹⁷ is independently chosen from i)—(CH₂)_(p)C(O)(CH₂)_(q)—; ii) —(CH₂)_(p)C(O)O(CH₂)_(q)—; iii)—(CH₂)_(p)OC(O)(CH₂)_(q)—; iv) —(CH₂)_(p)NH(CH₂)_(q)—; v)—(CH₂)_(p)C(O)NH(CH₂)_(q)—; vi) —(CH₂)_(p)NHC(O)(CH₂)_(q)—; vii)—(CH₂)_(p)NHC(O)NH(CH₂)_(q)—; viii) —(CH₂)_(p)NHC(═NH)NH(CH₂)_(q)—; andix) —(CH₂)_(p)—O—(CH₂)_(q)—; the indices p and q have the value from 0to 10; when p is 0 the —(CH₂)— units are absent; when q is 0 the —(CH₂)—units are absent; J is a unit having the formula:

wherein each R¹⁹ is each independently chosen from: i) hydrogen; ii)C₁-C₁₀ alkyl; or iii) a unit capable of reacting with a HB monomerhaving the formula:

or MOD monomer having the formula:

the R¹⁹ unit having the formula:

wherein R¹, R², R³, R^(9a), R^(9b), R¹⁰, R^(14a), R^(14b), R¹⁵ and R¹⁶are the same as defined herein above.
 35. A polymer according to claim34, wherein the XL unit has the formula:

wherein each R¹⁵ is independently hydrogen or methyl; R¹⁶ has theformula:

R¹⁹ is hydrogen, methyl, or ethyl; each value for the index q isindependently from 1 to
 4. 36. A polymer according to claim 35, whereineach R¹⁵ is methyl, R¹⁹ is ethyl, and each index q is equal to
 1. 37. Apolymer according to claim 1, wherein the LX unit when linking twopolymer chains has the formula:

R¹⁹ is hydrogen, methyl, ethyl, or a unit capable of forming a crosslinkto another polymer chain.
 38. A polymer according to claim 37, whereinthe LX unit has the formula:


39. A polymer according to claim 1, having the formula:

wherein the polymer comprises the following ratio: x is from 0.5 to 5: yis from 90 to 99: z is from 0.5 to 5, such that the sum of x+y+z=100.40. A polymer according to claim 39, wherein R¹, R², R³, R^(9a), R^(9b),R¹¹, R^(14a), R^(14b), and R¹⁵ are each independently hydrogen ormethyl.
 41. A polymer according to claim 40, wherein R¹, R², R^(9a),R^(9b), R¹⁴, and R^(14b) are hydrogen and R³, R¹¹, and R¹⁵ are methyl.42. A polymer according to claim 39, wherein Q has the formula:—[W]_(h)—[Y]_(j)-[Z]_(k)-R⁴ W is chosen from —C(O)O— or —C(O)NH—; Y ischosen from —(CH₂)_(s)— or —[(CH₂)_(t)O]_(w)(CH₂)_(s)—; the index s is 2or 3, the index t is 2 or 3; the index w is from 1 to 4; Z is chosenfrom: i) —C(O)—; ii) —C(O)O—; iii) —NH—; iv) —C(O)NH—; v) —NHC(O)—; orvi) —NHC(O)NH—; and R⁴ is chosen from:


43. A polymer according to claim 39, wherein R¹¹ is chosen from: a)—C(O)OH; b) —C(O)OCH₃; c) —C(O)OCH₂CH₃; d) —C(O)OCH₂CH₂CH₃; e)—C(O)OCH(CH₃)₂; f) —C(O)OCH₂CH₂CH₂CH₃; g) —C(O)OCH₂CH₂CH₂CH₂CH₃; and h)—C(O)OCH₂CH₂CH₂CH₂CH₂CH₃.
 44. A polymer according to claim 43, whereinR¹¹ is —C(O)OCH₂CH₂CH₂CH₃.
 45. A polymer according to claim 39, whereinR¹⁶ has the formula:

wherein R¹⁵ is hydrogen or methyl, each R¹⁹ is each independently chosenfrom: i) hydrogen; ii) C₁-C₁₀ alkyl; or iii) a unit capable of reactingwith a HB monomer having the formula:

or MOD monomer having the formula:

the R¹⁹ unit having the formula:

wherein R¹, R², R³R^(9a), R^(9b), R¹⁰, R^(14a), R^(14b), R¹⁵ and R¹⁶ arethe same as defined herein above.
 46. A polymer according to claim 45,wherein R¹⁶ has the formula:

wherein R¹⁹ is C₁-C₄ alkyl, and each of the indices q is equal to 1 or2.
 47. A polymer according to claim 39, having the formula:

wherein R¹³ is C₁-C₆ alkyl, R¹⁹ is hydrogen, methyl, ethyl, or a unitcapable of reacting with a HB monomer having the formula:

or MOD monomer having the formula:

the R¹⁹ unit capable of reacting has the formula:


48. A shape memory polymer precursor having the formula:

wherein the polymer comprises the following ratio: x is from 0.5 to 5: yis from 90 to 99: z is from 0.5 to 5, such that the sum of x+y+z=100;R²⁰ is a reactive unit capable of reacting with a di-functional moleculeto form a shape memory polymer according to claim 1; the di-functionalmolecule has the formula:R²²-J-R²² R²² each is independently chosen from i) ClC(O)(CH₂)_(b)—; ii)Cl(CH₂)_(b)—; iii) H₂N(CH₂)_(b)—; iv) HOC(O)(CH₂)_(b)—; v) HO(CH₂)_(b)—;vi) OCN(CH₂)_(b)—; and vii) N₃(CH₂)_(b)—; the index b is from 1 to 10; Jis a unit having the formula:

wherein each R¹⁹ is each independently chosen from: i) hydrogen; and ii)C₁-C₄ alkyl.
 49. A polymer precursor according to claim 48, wherein R¹,R², R³, R^(9a), R^(9b), R¹¹, R^(14a), R^(14b), and R¹⁵ are eachindependently hydrogen or methyl.
 50. A polymer precursor according toclaim 48, wherein R¹, R², R^(9a), R^(9b), R^(14a), and R^(14b) arehydrogen and R³, R¹¹, and R¹⁵ are methyl.
 51. A polymer precursoraccording to claim 48, wherein Q has the formula:—[W]_(h)—[Y]_(j)-[Z]_(k)-R⁴ W is chosen from —C(O)O— or —C(O)NH—; Y ischosen from —(CH₂)_(s)— or —[(CH₂)_(t)O]_(w)(CH₂)_(s)—; the index s is 2or 3, the index t is 2 or 3; the index w is from 1 to 4; Z is chosenfrom: i) —C(O)—; ii) —C(O)O—; iii) —NH—; iv) —C(O)NH—; v) —NHC(O)—; orvi) —NHC(O)NH—; and R⁴ is chosen from:


52. A polymer precursor according to claim 48, wherein R¹¹ is chosenfrom: a) —C(O)OH; b) —C(O)OCH₃; c) —C(O)OCH₂CH₃; d) —C(O)OCH₂CH₂CH₃; e)—C(O)OCH(CH₃)₂; f) —C(O)OCH₂CH₂CH₂CH₃; g) —C(O)OCH₂CH₂CH₂CH₂CH₃; and h)—C(O)OCH₂CH₂CH₂CH₂CH₂CH₃.
 53. A polymer precursor according to claim 52,wherein R¹¹ is —C(O)OCH₂CH₂CH₂CH₃.
 54. A polymer precursor according toclaim 48, wherein R²⁰ is a reactive moiety chosen from: i) —C(O)OR; ii)—NCO; and iii) —N₃; R²² is hydrogen or C₁-C₄ linear or branched alkyl.55. A polymer precursor according to claim 48, wherein the di-functionalmolecule is chosen from: i) HO(CH₂)_(n)OH; ii) H₂N(CH₂)_(n)NH₂, and iii)OCN(CH₂)_(n)NCO; wherein the index n is from 2 to
 10. 56. A polymeraccording to claim 1, having the formula:

wherein R¹⁶ is a unit capable of photo crosslinking with another R¹⁶unit; the polymer comprises the following ratio: x is from 0.5 to 5:y isfrom 90 to 99:z is from 0.5 to 5, such that the sum of x+y+z=100.
 57. Apolymer according to claim 1, wherein the XL unit has the formula:

wherein the index n is from 1 to 4; R^(14a), R^(14b), and R¹⁵ are eachindependently chosen from: iii) hydrogen; and ii) C₁-C₄ alkyl; R¹⁶comprises a photo reactive moiety, RM, capable of reacting with anotherphoto reactive moiety in the presence of UV light to form a crosslink.58. The polymer according to claim 57, wherein XL is formed from amonomer having the formula:

the index p is from 1 to
 10. 59. The polymer according to claim 58,wherein the XL monomer has the formula:


60. A shape memory polymer precursor having the formula:

wherein the polymer comprises the following ratio: x is from 0.5 to 5:yis from 90 to 99:z is from 0.5 to 5, such that the sum of x+y+z=100; R²⁰is a reactive unit capable of reacting with another R²⁰ unit in thepresence of UV light to form a crosslinking unit.
 61. A polymerprecursor according to claim 60, wherein R²⁰ has the formula:

the index p is from 1 to
 10. 62. A polymer formed by reacting: a) fromabout 0.5 to about 5 mol % of a monomer having the formula:

b) from about 90 to about 99 mol % of a monomer having the formula:

c) from about 0.5 to about 5 mol % of a monomer having the formula:

wherein: each R¹ and R² is independently chosen from: i) hydrogen; ii)C₁-C₆ alkyl; iii) halogen; iv) cyano; and v) phenyl; R³ is chosen from:i) hydrogen; and ii) C₁-C₆ alkyl; and Q is a unit having at least onehydrogen bond donor moiety or at least one hydrogen bond acceptormoiety; the index m is from 1 to 4; each R^(9a), R^(9b), and R¹⁰ areindependently chosen from: i) hydrogen; or ii) C₁-C₄ alkyl; R¹¹ is aunit chosen from; i) hydrogen; i) C₁-C₄ linear or branched alkyl; ii)—NR^(12a)R^(12b); iii) —C(O)OR³; iv) —C(O)R¹³; and v)—C(O)NR^(12a)R^(12b); wherein R^(12a), R^(12b), and R¹³ are eachindependently hydrogen or C₁-C₁₀ alkyl; R^(14a), R^(14b), and R¹⁵ areeach independently chosen from: iv) hydrogen; and ii) C₁-C₄ alkyl; R¹⁶has the formula:—R¹⁷-J-R¹⁷— each R¹⁷ is independently chosen from i)—(CH₂)_(p)C(O)(CH₂)_(q)—; ii) —(CH₂)_(p)C(O)O(CH₂)_(q)—; iii)—(CH₂)_(p)OC(O)(CH₂)_(q)—; iv) —(CH₂)_(p)NH(CH₂)_(q)—; v)—(CH₂)_(p)C(O)NH(CH₂)_(q)—; vi) —(CH₂)_(p)NHC(O)(CH₂)_(q)—; vii)—(CH₂)_(p)NHC(O)NH(CH₂)_(q)—; viii) —(CH₂)_(p)NHC(═NH)NH(CH₂)_(q)—; andix) —(CH₂)_(p)O(CH₂)_(q)—; the indices p and q have the value from 0 to10; when p is 0 the —(CH₂)— units are absent; when q is 0 the —(CH₂)—units are absent; J is a unit having the formula:

wherein each R¹⁹ is each independently chosen from: i) hydrogen; or ii)C₁-C₁₀ alkyl.
 63. A medical device comprising one or more polymersaccording to claim
 1. 64. The medical device of claim 63, chosen fromstents, sutures, vascular compresses, and vascular clips.
 65. A hearingsafety device comprising one or more polymers according to claim
 1. 66.The hearing safety device of claim 65, wherein the device is an earplug.